Ive played at the pro level. Nobody prefires with perfect robotic consistency.
I dont care if it takes 50 matches of data for the statistical model to call it inhuman.
Valve has enough data that they could easily make the threshold for a ban something like '10x more consistent at pre-firing than any pro has ever been' with a high confidence borne over many engagements in many matches.
Then all you need to do to fool this anticheat is to add some randomness to the cheat.
You've made them the same as the best players. Otherwise we're banning the best players.