HiDPI turns off when I increase resolution on Dell U3425WE (3440x1440) (USB-C)

[sahasvat]

Description
Hi, I’m using BetterDisplay mainly for HiDPI.

I upgraded to a Dell U3425WE (3440 x 1440) and HiDPI is not working as expected:
• When I enable HiDPI, the monitor’s resolution drops automatically.
• If I use the slider to increase the resolution back to 3440 x 1440, HiDPI turns off by itself.

So I can’t keep HiDPI enabled while using the monitor’s native resolution.

Also, I’m running the monitor at 3440 x 1440 @ 120Hz

HiDPI works perfectly on my older 1080p LG monitor.

My setup
• BetterDisplay: 4.1.5
• Mac: MacBook Pro M4 Pro
• macOS: 26.2 (stable)
• Monitor: Dell U3425WE (3440 x 1440)
• Connection: [USB-C]

[waydabber]

Some Macs (like the M4) limit the max HiDPI resolution for certain displays (the limit is probably 3072px horizontally for this Mac + display combo). You can check the max limits under Display Information... > Capabilities under the display's app settings pane.