All Unity games give the same error: Couldn't switch to requested monitor resolution

Compatibility Report

• Name of the game with compatibility issues: Ori and the Will of the Wisps, Among Trees, Firewatch, Getting over it, etc...

System Information

• GPU: RTX 3070 (also tested on GTX 1060)
• Driver/LLVM version: nvidia 455.45.01
• Kernel version: 5.9.14-2-MANJARO
• Link to full system information report as Gist:
• Proton version: Experimental

I confirm:

• that I have checked whether there are updates for my system available.
• that I haven't found an existing compatibility report for this game.

oriwotw_d3d11.log (I don't have a steam version of this game, so this is the only log I got)

Symptoms

When I try to launch a Unity game with Proton outside of Steam with the following command: ~/.steam/steam/steamapps/common/Proton\ -\ Experimental/proton run /game/path/here.exe, this error appears.

If I run the games with raw wine (latest from my package manager), most games seem to at least launch, although they have poor performance or major graphical glitches.

In games that show the Unity resolution selector window, the same error appears for all combinations of the resolutions and the fullscreen setting.

Reproduction

Try launching a game with the command mentioned above.

Start by reproducing the issue with the listed Proton command and inspect the linked oriwotw_d3d11.log alongside the Unity resolution-selector behavior. Done means the affected Unity games launch through Proton without the “Couldn't switch to requested monitor resolution” error across the reported resolution and fullscreen combinations.