Yes, and I’ve seen it happening. Usually it doesn’t instantly brick every PC, but it can sometimes brick certain PCs with specific configurations. Then it will be silently patched without acknowledgement for the bug.
I’ve seen it mess with (and crash) graphics and network drivers, rendering PCs useless until forced reboot. It can also mess up other games, processes, and even updates.
People have been warning gamers about kernel level anticheats since they were introduced, because no userland code should run with that level of privileges, period. However, people still installed those games not really understanding the threat, and that’s why we have so many games with a kernel anticheat.