My brother claims that Vanguard for League can do the same to gaming PCs that install it as CrowdStrike did to businesses who installed that, is this true? Does Vanguard have as much access/power?
That unfortunately means, you can't play a lot of games. And for most people it's practically unknowable what the installer is doing, they don't expect a game to nuke their computer.
There needs to be accountability and a certain level of trust. Microsoft shouldn't allow kernel drivers for crap like anti cheat.
That's... not remotely true? Linux can absolutely install kernel drivers. If you mean running windows games under wine then sure, but then we're no longer talking apples:apples. You could do the same thing on windows by running a game in a VM.