Magiilaro

You can’t really change the code of the windows Kernel and boot your own, that’s one of the things stopping people now

Yes, but with a modified Kernel you can fake what the anticheat reads when it checks the key, so you just feed it the key it wants to see instead of your own. The anticheat module would need run on a higher level then the Kernel itself to prevent that, for example alongside the CPU (like the Intel Management Engine).

You can add your own signing keys to the UEFI and boot an modified bootloader and Kernel that you have signed yourself. So yes, it is possible to “lie”

For such a locked down system, akin to game consoles or smartphones, would be needed. And even those get jail broken and manipulated, so “total security” on there is not complete but easier to check and ensure. Another way to make sure that the code is not manipulated would be to put all those games into the cloud and have every player only play via streaming. All the code would then run on secured, locked down and verified machines.

The native windows version of teams is also only a glorified web view.