I removed Windows from my machine and have been playing WoW on Garuda Linux since April. I installed via Lutris and use GE-proton with umu-launcher (simply using GE-Proton within latest Lutris uses umu) and it works every time without fail.
First, for WoW there is no separate cheat detector that somehow figures out “oh they’re on Linux, we must ban them”.
Second, WoW plays considerably better on Linux for me (based on the framerates I’m seeing in various locations in Azeroth). Granted, I decided to dump NVIDIA so I didn’t have to deal with their closed platform garbage.
Lastly, yes, anti-cheat is an issue, but not because of you running Linux — it’s because of game companies fundamentally misunderstanding operating systems. There is no easier method of cheating on Linux than there is on Windows especially if the game company properly supports Linux. So if a company were to ban you, either you are doing something ban-worthy (and running Linux objectively is not), or the company is garbage because they don’t understand what they’re doing.
I have seen no evidence to support Blizzard banning people for playing WoW on Linux. Show me a preponderance of evidence of this that isn’t possibly some other ban-worthy issue, and I will happily change my mind.