The main issue nowadays is anticheat. If you play esports (league of legends,apex legend, fortnite), you will have trouble. Pretty much everything else will be good to go.

Nobara is probaly a good choice, never used to be but looks good.

Only issue about linux gaming is anti-cheats, like if your friend wants to play valorant, r6, fortnite, or any new call of duty game, hes kinda screwed. You also have games like apex which work now because EAC supports proton, but ever since EA made their own anti cheat, its only a matter of time.

If you’re doing it for a friend make sure you ASK if they want Linux, don’t force it on them man that’s not cool. Most normies just want to use Windows for the compatibility and ease of use (call it handholding and restrictive all you want).

Proton is awesome! I have two games out of my ~100 game library that simply don’t work at all. Every other game either works out of the box, or works with a little bit of tinkering. Of the two that don’t work, one is because of anti cheat software, and the other I don’t know why (Space Engineers, just doesn’t work).

Been using Proton for a long time and my experience has been very positive overall. Most games work without any problems, the few that do usually have easy workarounds. The big stopping point for Proton is that many multiplayer games that use anti cheat don’t work well. Aside from that I use it for all sorts of games.

You can see how well each game runs on https://www.protondb.com/

As for distro, Proton should work pretty much everywhere but some distros provide a better out of the box experience.