BenQ RD280U vs Gigabyte M34WQ-SA: Gigabyte’s ultrawide gaming mode needs separate laptop power above 18W
The short answer
Choose RD280U for a tall 3:2 app layout at readable scaling, or to replace a charger when operating or startup demand exceeds 18W and both fit its supported up-to-90W PD profile through the video/data USB-C upstream and full-featured power-rated cable, with mains power. Choose M34WQ-SA for a supported 21:9 layout, accepting separate power above 18W. Verify host, cable and desk fit. BenQ’s native 3840 by 2560 reaches 60Hz over DP/USB-C or 50Hz over HDMI. Gigabyte’s native 3440 by 1440 reaches 144Hz over DP/Type-C or 100Hz over HDMI. Neither combines that native ultrawide 144Hz mode with more than 18W laptop power. KVM is shared setup, not a deciding advantage.
Before you choose
The reasoning and the trade-offs
Choose the window arrangement before the bigger diagonal
At readable scaling, a tall editor can favor RD280U’s 3:2 shape, while an app or game supporting 21:9 can favor M34WQ. Check the actual layout rather than diagonal size. BenQ needs 610.4 mm width and compatible native 3840 by 2560 output at up to 60Hz over DP/USB-C or 50Hz over HDMI. Gigabyte needs 817.7 mm width and native 3440 by 1440 at up to 144Hz over DP/Type-C or 100Hz over HDMI, plus separate power above 18W. If both layouts fit, shape stops deciding. Neither guarantees extra readable lines or productivity.
What this is based on
The native dimensions, physical shape and supported input timings identify different layout choices. They do not measure how much useful content a particular person can read or how much of a game world the software renders. The reversal is the buyer’s actual app layout, not the larger diagonal or an extra-pixel calculation.
Main trade-off
BenQ RD Series 28-inch Programming Monitor
The native 3:2 panel reaches 60Hz through DP or USB-C and 50Hz through HDMI. Check the exact host, cable and readable app scaling. It is not an ultrawide 144Hz display, and the original RD280U stand does not pivot. The chassis is 610.4 mm wide with 244.5 mm stand depth.
Main trade-off
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
The 817.7 mm-wide chassis needs space, and an app or game must support the wide layout you want. Native 3440 by 1440 reaches up to 144Hz through compatible DP/Type-C and 100Hz through HDMI. The timing table does not promise game frame rates or simultaneous maximum refresh, HDR, adaptive sync and PIP/PBP.
RD280U
BenQ RD Series 28-inch Programming Monitor
Choose it for
Choose RD280U when your actual apps favor its tall 3:2 layout at readable scaling and its 610.4 mm width fits. Verify host/cable output at native 3840 by 2560: up to 60Hz through DP/USB-C or 50Hz through HDMI. A supported wide layout can reverse this choice. An unsupported required timing rules it out.
Choose RD280U to leave the charger packed when operating or startup demand exceeds 18W and both fit its supported up-to-90W PD profile. Verify native 3840 by 2560 at 60Hz from the USB-C host, a full-featured power-rated cable, the video/data upstream, mains power and Power Awake for standby charging. This reason disappears if a separate charger can stay.
Main trade-off
The native 3:2 panel reaches 60Hz through DP or USB-C and 50Hz through HDMI. Check the exact host, cable and readable app scaling. It is not an ultrawide 144Hz display, and the original RD280U stand does not pivot. The chassis is 610.4 mm wide with 244.5 mm stand depth.
Choose M34WQ-SA when the app/game supports your intended 21:9 layout and its 817.7 mm width fits. Verify native 3440 by 1440 with the actual host/cable/mode: up to 144Hz through DP/Type-C or 100Hz through HDMI. Retain separate laptop power above its compatible 18W ceiling. If the app cannot use the width or the required timing is unsupported, reconsider.
Main trade-off
The 817.7 mm-wide chassis needs space, and an app or game must support the wide layout you want. Native 3440 by 1440 reaches up to 144Hz through compatible DP/Type-C and 100Hz through HDMI. The timing table does not promise game frame rates or simultaneous maximum refresh, HDR, adaptive sync and PIP/PBP.
Analysis updated , Catalog updated , Amazon.com / United States
About this comparison
Compare BenQ RD280U and Gigabyte M34WQ-SA for tall documents, supported ultrawide layouts, laptop charging and shared keyboard setup.
A laptop and desktop sharing one screen, keyboard and mouse can plausibly use either monitor. Decide what that screen must show at readable settings, then whether plugging in the laptop must also replace its charger. A wide game layout can favor Gigabyte while the same laptop’s power needs favor BenQ, so settle both before ordering.
Winner by situation
Start with what you need it to do
A tall document or editor layout is the priority at readable scaling
RD280U’s 3:2 panel is a candidate only if the actual app works at readable scaling and 610.4 mm width fits. Verify native 3840 by 2560 at up to 60Hz through DP/USB-C or 50Hz through HDMI with your host/cable. A supported ultrawide need can reverse the choice. Unsupported timing rules it out.
BenQ RD Series 28-inch Programming Monitor
Better fit
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Caution
The app or game uses an ultrawide layout, and separate laptop power is acceptable
M34WQ needs actual app/game support for 21:9 and 817.7 mm of width. Verify native 3440 by 1440 at up to 144Hz through DP/Type-C or 100Hz through HDMI with the chosen host/cable/mode. Keep separate power above its compatible 18W ceiling. Width alone supplies no benefit when the app does not use it.
BenQ RD Series 28-inch Programming Monitor
Caution
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Better fit
Either layout works, but a compatible laptop needs more than 18W and up to 90W without its own charger
BenQ can remove the charger only when operating/startup demands both fit its supported up-to-90W profile. Use a host supporting native 3840 by 2560 at 60Hz, the video/data USB-C upstream and a full-featured power-rated cable, with mains power and Power Awake for standby charging. Gigabyte stops at 18W. If the charger can stay, this reason disappears.
BenQ RD Series 28-inch Programming Monitor
Better fit
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Not suitable
Native 3440 by 1440 at 144Hz and more than 18W of monitor-supplied laptop power are both mandatory
Gigabyte supports that native mode through compatible DP/Type-C but its USB-C ceiling is 18W. BenQ offers a different native tall panel at up to 60Hz. Keep separate power to reopen Gigabyte, or accept BenQ’s layout with verified host/profile/cable, correct upstream, mains and Power Awake for standby charging. Neither supplies more than 90W.
BenQ RD Series 28-inch Programming Monitor
Not suitable
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Not suitable
The charger can stay connected and either screen layout meets the job
The laptop-power reason no longer decides this choice. Similar means both remain candidates, not equal image quality. Compare physical fit, the exact current offers and your host’s actual output. BenQ native refresh is up to 60Hz through DP/USB-C or 50Hz through HDMI. Gigabyte native refresh is up to 144Hz through DP/Type-C or 100Hz through HDMI. Both still need correctly connected and mapped USB upstream data for KVM. If either host path cannot meet the required timing, do not choose it on socket shape alone.
BenQ RD Series 28-inch Programming Monitor
Similar
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Similar
What matters in practice
The differences that matter
01
Choose the window arrangement before the bigger diagonal
At readable scaling, a tall editor can favor RD280U’s 3:2 shape, while an app or game supporting 21:9 can favor M34WQ. Check the actual layout rather than diagonal size. BenQ needs 610.4 mm width and compatible native 3840 by 2560 output at up to 60Hz over DP/USB-C or 50Hz over HDMI. Gigabyte needs 817.7 mm width and native 3440 by 1440 at up to 144Hz over DP/Type-C or 100Hz over HDMI, plus separate power above 18W. If both layouts fit, shape stops deciding. Neither guarantees extra readable lines or productivity.
How we reached this conclusion
The native dimensions, physical shape and supported input timings identify different layout choices. They do not measure how much useful content a particular person can read or how much of a game world the software renders. The reversal is the buyer’s actual app layout, not the larger diagonal or an extra-pixel calculation.
02
The charger decision survives when either screen layout works
Keep either acceptable screen layout fixed. RD280U can remove the charger when operating or startup demand exceeds Gigabyte’s 18W ceiling and both fit BenQ’s compatible up-to-90W profile. That requires a native 3840 by 2560 60Hz USB-C host, full-featured power-rated cable, the video/data upstream, mains power and Power Awake for standby charging. If the charger can stay attached, the power reason disappears. A laptop within Gigabyte’s supported 18W profiles needs its own compatibility check. Neither wattage establishes charging time.
How we reached this conclusion
BenQ’s 90W upstream ceiling and Gigabyte’s 18W maximum profile create a conditional connection difference independent of the screen shape. Gigabyte profile arithmetic is max(5 times 3, 9 times 2, 12 times 1.5, 15 times 1) = 18W. The requested voltage/current profile, cable, operating demand, startup demand and monitor power state remain necessary checks.
03
Do not ask one cable to satisfy incompatible priorities
A mandatory native 3440 by 1440 144Hz signal plus more than 18W from the monitor rules out both. RD280U has a different native panel and 60Hz maximum. M34WQ covers that timing through compatible DP/Type-C but stops at 18W power. Keeping a separate charger reopens Gigabyte. Accepting BenQ’s tall 60Hz layout reopens up-to-90W power only with a matching host/profile, full-featured cable, correct upstream, mains and Power Awake for standby. Neither supplies more than 90W or fixes an unsupported host.
How we reached this conclusion
The combined requirement intersects a native display timing with a laptop power requirement. Each monitor misses a different part. KVM does not raise the available charging power, and an HDMI or DP video cable does not carry USB peripheral data.
Choice A
RD280U
BenQ, RD280U
RD Series 28-inch Programming Monitor
BenQ RD280U is a 28.2-inch 3:2 monitor with a 3840 by 2560 panel, up to 60Hz through DP or USB-C and 50Hz through HDMI. Its correct USB-C upstream can supply up to 90W to a compatible laptop. Standby charging needs Power Awake. KVM requires the separate host video and USB paths.
Best matched use
Choose RD280U when your actual apps favor its tall 3:2 layout at readable scaling and its 610.4 mm width fits. Verify host/cable output at native 3840 by 2560: up to 60Hz through DP/USB-C or 50Hz through HDMI. A supported wide layout can reverse this choice. An unsupported required timing rules it out.
Checked facts
Arrange the work you actually keep open: 28.2-inch 3:2, 3840 by 2560
The input changes the native refresh ceiling: DP and USB-C 60Hz, HDMI 50Hz
What stays attached to the laptop: Up to 90W from the correct USB-C upstream
Both can share a keyboard and mouse: USB-C video/data plus DP or HDMI with USB-B
Gigabyte M34WQ-SA is a flat 34-inch 21:9 monitor at 3440 by 1440, up to 144Hz through compatible DP or Type-C and 100Hz through HDMI. Its USB-C power profiles peak at 18W. KVM Wizard pairs the video inputs with USB-B and USB-C data. Allow for separate laptop power when needed.
Best matched use
Choose M34WQ-SA when the app/game supports your intended 21:9 layout and its 817.7 mm width fits. Verify native 3440 by 1440 with the actual host/cable/mode: up to 144Hz through DP/Type-C or 100Hz through HDMI. Retain separate laptop power above its compatible 18W ceiling. If the app cannot use the width or the required timing is unsupported, reconsider.
Checked facts
Arrange the work you actually keep open: 34-inch 21:9, 3440 by 1440
The input changes the native refresh ceiling: DP and Type-C 144Hz, HDMI 100Hz
What stays attached to the laptop: USB-C power profiles peak at 18W
Both can share a keyboard and mouse: Video inputs paired with USB-B and USB-C in KVM Wizard
Meaningful differences between BenQ RD Series 28-inch Programming Monitor and Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
What changes
BenQ RD Series 28-inch Programming Monitor
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
Why it matters
Arrange the work you actually keep open
BenQ RD Series 28-inch Programming Monitor28.2-inch 3:2, 3840 by 2560
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor34-inch 21:9, 3440 by 1440
Why it mattersTry the editor, document, reference windows or game layout at the scaling and text size you will use. BenQ offers a tall shape in a narrower chassis. Gigabyte offers a physically wider shape for an app or game that uses it. Gigabyte does not have more horizontal pixels than BenQ. Neither specification establishes a fixed number of extra lines, better text comfort or faster work.
The input changes the native refresh ceiling
BenQ RD Series 28-inch Programming MonitorDP and USB-C 60Hz, HDMI 50Hz
Why it mattersCheck the entire signal path before buying for a particular refresh rate. A laptop or adapter that only provides an incompatible timing can defeat either choice. A supported timing is not a measured game frame rate, response time or motion-quality result. Do not assume maximum refresh, HDR, adaptive sync and two-source display modes all work together.
What stays attached to the laptop
BenQ RD Series 28-inch Programming MonitorUp to 90W from the correct USB-C upstream
Gigabyte M34WQ 34-inch Ultrawide Gaming MonitorUSB-C power profiles peak at 18W
Why it mattersFor a compatible laptop needing more than 18W but within BenQ’s supported power profiles, BenQ can remove the separate charger from this desk connection. Gigabyte requires another adequate power source. This can decide the purchase even when either screen layout is acceptable. If the existing charger can stay connected, that reason to choose BenQ falls away. Neither powers a laptop that requires more than its supported profile.
Both can share a keyboard and mouse
BenQ RD Series 28-inch Programming MonitorUSB-C video/data plus DP or HDMI with USB-B
Gigabyte M34WQ 34-inch Ultrawide Gaming MonitorVideo inputs paired with USB-B and USB-C in KVM Wizard
Why it mattersBoth require USB data connections as well as video. This is not a reason to choose one merely because its specifications say KVM. On BenQ, proper cabling enables KVM and the default Function Key cycles inputs. On Gigabyte, bind the inputs in KVM Wizard and keep KVM enabled. These controls switch the connected computer. They do not combine two sessions or establish identical switching reliability.
Check the complete physical and power setup
BenQ RD Series 28-inch Programming Monitor610.4 mm wide, 244.5 mm stand depth
Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor817.7 mm wide, 244.3 mm stand depth
Why it mattersGigabyte needs more clear width, while the listed stand depths are nearly the same. Measure space for the screen, stand, laptop, cables and any separate charger. BenQ’s original stand does not pivot, so its tall screen shape is not a promise of portrait rotation. Both monitors need mains power. Neither is a portable display powered solely by the laptop.
What you give up
Every choice has a cost
If you choose BenQ RD Series 28-inch Programming Monitor
The 90W ceiling belongs to the video/data USB-C upstream, not the 7.5W downstream port. Verify the PD profile, full-featured cable, operating/startup demands and mains power. Standby charging needs Power Awake. Retain the laptop adapter when necessary. Shared KVM requires compatible paired video/data paths and the setup checklist.
If you choose Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor
USB-C peaks at 18W, leaving a higher-power laptop on its own supply. Charging behavior depends on operating state and the checklist settings. KVM needs compatible mapped video/data paths and peripherals attached to the monitor. A Type-C cable is not listed in the manual’s package contents.
Recommendation switch
The decision flips if...
A tall editor or document layout matters more than a wide game view
Choose BenQ RD Series 28-inch Programming Monitor. Verify readable scaling and app fit, 610.4 mm width and native 3840 by 2560 from the actual host/cable at up to 60Hz over DP/USB-C or 50Hz over HDMI. A wide-layout requirement reverses the choice. Unsupported required timing rules it out.
A supported ultrawide layout matters more, and separate laptop power is fine
Choose Gigabyte M34WQ 34-inch Ultrawide Gaming Monitor. The app/game must use 21:9 and 817.7 mm width must fit. Verify native 3440 by 1440 from the host/cable at up to 144Hz over DP/Type-C or 100Hz over HDMI. Keep separate power above the compatible 18W ceiling.
A compatible laptop needs more than 18W, fits BenQ’s profiles and must leave its charger packed
Choose BenQ RD Series 28-inch Programming Monitor. Both operating and startup needs must fit a supported up-to-90W profile. Use a native 3840 by 2560 60Hz USB-C host, full-featured power-rated cable and video/data upstream, with mains and Power Awake for standby. If the charger can stay, this benefit disappears.
Native 3440 by 1440 at 144Hz and more than 18W from the monitor are both required
Choose neither. Gigabyte’s compatible DP/Type-C supports native 3440 by 1440 at 144Hz but USB-C power stops at 18W. BenQ’s different native panel stops at 60Hz. Separate power reopens Gigabyte. BenQ needs acceptance of its layout and a verified host/profile/cable, correct upstream, mains and Power Awake for standby. Neither supplies more than 90W.
What matters in practice
Before you choose
Check your actual app layout first, then decide whether the laptop charger must stay in the bag.
Check these before buying
Confirm the exact BenQ RD280U with its original standard stand or Gigabyte M34WQ-SA. RD280UG, RD280UA and other M-series displays are different purchases. Check the condition, supplied cables, stand, seller and return terms. No current price, stock, delivery or seller advantage is claimed.
Use the actual apps, readable text size and operating-system scaling to judge the shape. Do not compare both at an artificially identical scaling percentage and assume equal text size. BenQ is a 28.2-inch 3840 by 2560 3:2 screen. Gigabyte is a 34-inch 3440 by 1440 21:9 screen. Its physically wider panel does not contain more horizontal pixels than BenQ. A game must support the desired ultrawide layout to benefit from it.
Check native output on the exact computer, graphics hardware, operating system, adapter and cable. RD280U supports native 3840 by 2560 up to 60Hz through DP 1.4 or USB-C, and up to 50Hz through HDMI 2.0. M34WQ supports native 3440 by 1440 up to 144Hz through DP or Type-C, and up to 100Hz through HDMI 2.0. Verify the selected signal in the host and monitor menus. These are supported timings, not a promise that a game renders that many frames.
A USB-C socket alone does not establish video, data or charging compatibility. Check the host’s DisplayPort Alt Mode output, supported timing and USB Power Delivery profile, plus a cable that carries video, data and the required power. BenQ recommends a USB-IF-certified full-featured cable when buying one separately. Check the exact Mac model and chip rather than assuming every Mac has the same display support.
For RD280U KVM, connect the keyboard and mouse to the monitor. Connect one computer to the USB-C video/data upstream and the other through DisplayPort or HDMI plus USB-B upstream. Correct connections enable KVM automatically. The default Function Key cycles available input sources. A forced USB-C Upstream selection in the KVM menu can keep peripheral control on that host, so check the selected mode if control does not follow the picture. Power Awake is a standby-charging condition here, not an extra KVM step transferred from another BenQ model.
For M34WQ KVM, connect keyboard and mouse to downstream ports and give each computer both video and USB data. A common setup is Type-C video/data for the laptop and DP or HDMI plus USB-B for the desktop. In KVM Wizard, assign the actual video input to USB-B, then the input for USB-C. Set KVM ON and use the KVM button or controls. After a reset, HDMI 1 pairs with USB-B and Type-C pairs with USB-C. Video alone cannot switch USB peripherals.
If removing the laptop charger matters, match its operating and drained-battery startup demand to BenQ’s USB Power Delivery profiles, up to 20V/4.5A or 90W. Use the 90W video/data upstream, not the separate 7.5W USB-C downstream. Keep monitor mains power connected and enable System > Power Awake for standby charging. Keep the original laptop adapter if its requirement exceeds the available power or its charging profile is incompatible.
Gigabyte’s USB-C profiles are 5V/3A, 9V/2A, 12V/1.5A and 15V/1A. Their highest listed power is 18W. Keep a separate suitable laptop charger when that is insufficient. Standby Charge changes Type-C charging behavior in monitor standby, while USB Charge controls USB power in DC-off or saving mode. Neither setting turns the port into a 90W laptop supply. Do not assume the same power in every operating state.
BenQ’s USB-C Configuration table lists native 3840 by 2560 at 60Hz in both USB 3.2 and USB 2.0 modes, with respective data ceilings of 5 Gbps and 480 Mbps. Do not import the PD3205U’s 4K30 tradeoff into RD280U. Gigabyte’s Type-C Compatibility option addresses hosts without DSC. Verify the actual timing after changing it. Neither the port list nor this comparison promises maximum refresh, USB speed, HDR, adaptive sync and PIP/PBP together.
Measure 610.4 mm width and 244.5 mm stand depth for BenQ, or 817.7 mm width and 244.3 mm stand depth for Gigabyte, plus cable and charger access. RD280U’s original stand does not pivot. Check selected-offer cable contents. BenQ’s US specification lists HDMI, USB 3.2 and USB-C with regional variation. Gigabyte’s manual lists HDMI, DP and USB cables but does not list a supplied Type-C cable. Budget any missing cable for the complete two-computer setup.
Do not choose this pair on an assumed two-screen Mac daisy chain. BenQ’s MST instructions require compatible DP 1.4 graphics and exclude MacBook operation. Its listed first-screen 3840 by 2560 at 60Hz configuration gives a second 3840 by 2160 screen at 30Hz. That is not two native 60Hz displays. This comparison recommends a single shared display and does not promise any combined MST, KVM and maximum-bandwidth setup.
What this comparison cannot tell you
This is a manufacturer-document comparison, not a hands-on test of text comfort, eye strain, color accuracy, latency, game frame rates, switching reliability or laptop charging under load.
The BenQ operating evidence is a manufacturer-authored RD-series manual read from a public mirror, using the exact RD280U sections. Its official US specifications and exact-model timing file corroborate the relevant facts. No RD280UG or arm-model feature is transferred.
The supported screen layout and laptop power path are separate decisions. Refresh and chassis dimensions qualify the layout choice. Both models having KVM is shared setup information, not a third independent advantage.
No fixed extra lines of code, equal text size at equal scaling, universal ultrawide game support, universal Mac compatibility or simultaneous maximum-feature combination is established. An existing suitable dock or separate charger can remove the laptop-power reason.
What the facts say
What the comparison shows
Useful conclusions from the current computer monitors comparison, followed by the checked facts used to reach them.
See the checked facts and calculation notes
Compared set
2 models
Source records
4 for the products shown
Catalog updated
Facts and source records used for the products in this recommendation
Product
Needs matched
Checked facts
Source records
BenQ RD Series 28-inch Programming Monitor
Choose RD280U when your actual apps favor its tall 3:2 layout at readable scaling and its 610.4 mm width fits. Verify host/cable output at native 3840 by 2560: up to 60Hz through DP/USB-C or 50Hz through HDMI. A supported wide layout can reverse this choice. An unsupported required timing rules it out.
Choose RD280U to leave the charger packed when operating or startup demand exceeds 18W and both fit its supported up-to-90W PD profile. Verify native 3840 by 2560 at 60Hz from the USB-C host, a full-featured power-rated cable, the video/data upstream, mains power and Power Awake for standby charging. This reason disappears if a separate charger can stay.
Arrange the work you actually keep open: 28.2-inch 3:2, 3840 by 2560
The input changes the native refresh ceiling: DP and USB-C 60Hz, HDMI 50Hz
What stays attached to the laptop: Up to 90W from the correct USB-C upstream
Both can share a keyboard and mouse: USB-C video/data plus DP or HDMI with USB-B
Check the complete physical and power setup: 610.4 mm wide, 244.5 mm stand depth
Choose M34WQ-SA when the app/game supports your intended 21:9 layout and its 817.7 mm width fits. Verify native 3440 by 1440 with the actual host/cable/mode: up to 144Hz through DP/Type-C or 100Hz through HDMI. Retain separate laptop power above its compatible 18W ceiling. If the app cannot use the width or the required timing is unsupported, reconsider.
Arrange the work you actually keep open: 34-inch 21:9, 3440 by 1440
The input changes the native refresh ceiling: DP and Type-C 144Hz, HDMI 100Hz
What stays attached to the laptop: USB-C power profiles peak at 18W
Both can share a keyboard and mouse: Video inputs paired with USB-B and USB-C in KVM Wizard
Check the complete physical and power setup: 817.7 mm wide, 244.3 mm stand depth
Open either model on Amazon to check the current price, customer reviews and delivery options.
RD280U
BenQ RD Series 28-inch Programming Monitor
Choose RD280U when your actual apps favor its tall 3:2 layout at readable scaling and its 610.4 mm width fits. Verify host/cable output at native 3840 by 2560: up to 60Hz through DP/USB-C or 50Hz through HDMI. A supported wide layout can reverse this choice. An unsupported required timing rules it out.
Choose RD280U to leave the charger packed when operating or startup demand exceeds 18W and both fit its supported up-to-90W PD profile. Verify native 3840 by 2560 at 60Hz from the USB-C host, a full-featured power-rated cable, the video/data upstream, mains power and Power Awake for standby charging. This reason disappears if a separate charger can stay.
Choose M34WQ-SA when the app/game supports your intended 21:9 layout and its 817.7 mm width fits. Verify native 3440 by 1440 with the actual host/cable/mode: up to 144Hz through DP/Type-C or 100Hz through HDMI. Retain separate laptop power above its compatible 18W ceiling. If the app cannot use the width or the required timing is unsupported, reconsider.
