I'd say that coverage is very, very substantial, but incomplete because some games use anti-cheat that is either extremely invasive and heavily relies on Windows internals, or is anti-cheat that the devs have configured to reject running in Proton.

Anything you'd want to play runs on Linux.

One that people keep commenting on is Battlefield 6, which has an absolutely perfect user experience in Linux.

If you play it on Windows it's a slow, buggy, crashy, half-finished mess that barely works is just no fun at all.

On Linux, it's perfect. It doesn't work at all, so you don't waste any time trying to enjoy the slow, buggy, crashy, half-finished mess.