About the AC, it's bad on purpose.
Valve have explicitly stated that their goal with VAC is not to ban as many cheaters as possible, it's to make sure that there are no false bans. Almost no one gets falsely banned with VAC, if you have a VAC ban there's a 99,97% chance that you cheated, and the remaining 0,03% are easily resolved through support tickets.
Other ACs like BattlEye don't have this hitrate, where they'll have a comparatively large amount of false bans compared to VAC.
But yeah, I see your point, just saying that Valve definitely could make a more trigger-happy Anti-cheat, but they choose not to in favor of precision.