Some cheats don’t even involve anything running on the hardware running the game. A raspberry Pi or something like that takes the video signal and mouse as input and acts as a mouse as output, analyses like 100x100 pixels around the reticle, and adjusts the mouse output to aim the reticle at any enemies it sees in that area.
You’d need some pretty good statistical analysis on the mouse signal to detect something like that, assuming the cheat is sophisticated enough to know it can’t break the laws of physics or natural human motion and thus keeps the first and second derivatives continuous (though bumping into your keyboard with your mouse will break the continuity of the second derivative and maybe even the first at mouse resolutions, but that happening consistently when you’re trying to shoot someone and resulting in high accuracy is very sus).
Or you could just make it shoot when the reticle is lined up with a hit and leave the mouse position alone entirely. Maybe set it up so it only does that even the player is holding a mouse button.
I think the endgame of the anti-cheat vs cheat arms race will be a system that limits cheaters to the best possible human skill, though I bet such a system will also catch some of the best players as it gets tuned or new stars rise up and beat the previous ones.
Instead of an arms race, they should back off on the day-to-day cheating detection so that cheaters spend time and resources on cheats that they can detect (but don’t ban immediately for so that they think they are avoiding detection), and then every now and then turn the cheating detection up and ban the cheaters.
Or maybe a shadow ban system where they detect cheaters and quietly move them to cheater queues. Maybe even add some bots that cheat even harder.
But the main thing is to get rid of any immediate and obvious feedback that a cheat isn’t good enough to beat their system so that those selling them think they can go to market with a shitty cheat rather than knowing they need to get better and most importantly, people writing reviews of the cheats will say the cheap ones work and the expensive ones aren’t necessary.