my ArchLinux config for proton-ge, hdr settings and selecting monitor.
If default it uses DisplayPort, if big picture it uses HDMI. It also sets up wayland hdr.
there are some other settings i use as defaults, like cpu topology or ntsync. If you got here by google feel free to remove the unnecessary stuff, I've commented parts setting monitor and hdr.
I don't remember how to check strings for display on wayland so you'll have to google it up if you need different ones.