Right click the game (on steam after adding it), go to Properties > Compatibility. Check the "Force the use of a specific Steam Play compatibility tool" box and select a Proton version, can pick any one to see which one works for you. You might have to select it twice as it might bug out the first time and default to whatever the first entry was. I just tested it on my CachyOS (Arch Linux) with Proton 10 and it works wonderfully