The game doesn’t even realise gamescope is there. That’s the beauty of it. As the game sees it, it’s just a regular monitor with the specs you gave it via commands

You can use gamescope. There are keyboard shortcuts to modify sharpen filter.

Used to be really finnicky but lately (last 6 months let’s say) it’s worked just fine. The only downside is that it might get hanged in the background and steam will show the game still running.

I’ve solved most of my monitor problems on Wayland by using Gamescope. For example Enlisted (native) will insist on spanning across my 2 1080 monitors, or Helldivers 2 won’t boot on fullscreen while showing a white line on borderless. Also most games won’t properly grab the cursor.

On any steam game add this as launch options:

gamescope -w 2560 -h 1440 -r 60 -f -e %command%

This will make the game think it’s always running in the foreground, and in the resolution/refresh rate you specify.

If you want to add extra commands, like mangohud or gamemoderun, put them before gamescope

Hope this helps ya, GL&HF