Some anticheats like EAC, GameGuard, XingCode do have Linux support that the game has to opt-in. I believe it is not kernel-based and is not Linux-native. Many non-competitive games do allow them.

At least I know that Helldivers 2 (GameGuard), DJMax Respect V (XingCode), Fantasy Life I (EAC) do works on Linux.

I wish that if they're happy with non kernel mode anti cheat on Linux, just do the same in Windows... Or just disable them if I don't use public matchmaking