There's hardware level (on a separate device) ability to capture video and send key/mouse now. Impossible to be detected by anticheat. https://wiki.sipeed.com/hardware/en/kvm/NanoKVM_Pro/cua.html

Yes, but that works just as readily on consoles as it does PCs, so it doesn’t affect immutable Steam any more or less than any other gaming steam. Sealed protections are still valuable regardless!