Arc Raiders is a great example of a modern and popular multiplayer game that works with proton. I haven't heard about it having a problem with cheating.
I think a big portion of that is the rather poorly made anti-tamper solution they are using called 'Theia' most cheat developers are too unintelligent to correctly reverse engineer this kind of binary obfuscation
Marvel Rivals, Age of Empires 2 DE, Path of Exile 1/2, Last Epoch, Fall Guys are other such examples. In fact, Marvel Rivals even explicitly mentioned Bazzite in one of their changelogs! I can't recall an instance when a major game name-dropped a (relatively) minor Linux distro like that.