Every Riot game requires Secure Boot for Vanguard to work. So does Tarkov and a lot of other games. It's not unique to those two.

And what the fuck would they want with your computer anyways? Are you afraid they're gonna steal the porn you stored on it? Secure Boot is literally a few checks on boot and the anti-cheat simply verifies these checks. There's nothing nefarious here, this is a lot less invasive than Riot Vanguard.