Hey I just wanted to share how I was able to get Marvel Rivals running, although I'm on a different distro it should work for you:
In the Launch options (right click game > properties > general tab) enter this:
SteamDeck=1 %command%
Then, it tricks the game into believing you are on steam deck, and it should run. If you want to disable the performance metrics, just press right shift+f12.
I'm a recent lifetime windows user to Linux but loving it! I've dual booted so I can still play stuff like fortnite/call of duty but surely those will come around as the user count climbs :)
Edit to add: I found this fix on protondb.com - you can usually find others posting helpful stuff there relating to any Linux game!
Two features I'd love to see are an option from the posts view for "Scroll to top", also while in a comments section the ability to "find/search" the various comments. Thanks so much :)