I played it twice on linux. It’s actually one of those games that run better than they do on windows thanks to the large amount of fixes and workarounds specific to this game that are in DXVK. You don’t even need to cap the framerate or limit the affinity to one core during the ending to prevent the helicopter bug. Personally, I would recommend playing a repack that already has all the community fixes for the game, but if you don’t know how to do it, just play it on steam and you’ll be fine.

https://www.protondb.com/app/12210 Here’s a page of people reviewing the Linux compatibility of GTA 4. Any game that is on Steam will have a page like this on ProtonDB.