Shoddy article by someone who hasn't looked into the matter at ALL !
Point 1 : ProtonDB is a website where Valve centralizes user reports on games that run on Proton. Proton is a Wine-based compatibility layer developed by Valve (it's technically a fork) and as such it's not new - Proton itself is a couple years old now, and Wine is getting on 30 years old.
So, it really is NOT in its infancy. Moreover, if a game is noted as running on ProtonDB, it also means that its attached anticheat system works too - so, the article is wrong here, several anticheat systems already work on Proton, but not all.
Point 2 : most anti-cheat software work by plugging themselves into Windows' kernel space and monitoring whatever the system is doing to make sure that nothing but themselves are tampering with a given game - they behave like the worst kind of rootkit, the spying one. Proton is user-space only and Linux is a secure kernel, so whenever an anticheat system can't load, it gets pissed off and prevents the game from loading. There are 3 things that can be done to solve this:
- allow Linux to be hacked as easily as the Windows NT kernel (not on my machine, thank you)
- make anti-cheat software behave in a less-hacky way (that requires the author of the anti-cheat software to be a good programmer)
- make anti-cheat software think it subverted the kernel for the currently running user (it's pretty much already the case, but it requires emulating the inner workings of the Windows kernel in user space, warts, bugs and all, which is a bit of a pain)
1 is a no-go, 2 is already somewhat under way (see : Doom Eternal), 3 is a moving target. Note that an anticheat system may stop working after a Windows update, for the same reason it won't run on Proton.