That sort of already exists - I believe a small number of games demand that you have Secure Boot enabled, meaning you should only have a Microsoft-approved kernel and drivers running. And then the anticheat is itself probably kernel level, so can see anything in userspace

It may still be possible to get round this by using your own machine owner key or using PreLoader/shim [1] to sign a hacked Windows kernel

[1] https://wiki.archlinux.org/title/Unified_Extensible_Firmware...