The hardware itself is obfuscation. What you're asking for does exist though, in the form of Android devices and game consoles. Was curious about Steam Deck and... interesting, no secure boot there.

Someone could build a desktop OS on top of an anticheat-friendly kernel, but it'd probably not be big enough for gamemakers to care, and Linux desktop people would be uninterested in it to say the lease. (I'm on a Mac btw, I have no horse in this race)