I'm not saying this is impossible, it certainly is possible, and clearing or disabling the TPM is always a good idea on used PC hardware or even new hardware. And I'm not saying I know if that's what actually happened here. But I have to put on my "press F to doubt" hat, and point out that realistically it always seems to turn out that like 95% of the time when someone claims they were "banned for cheating and this is the reason why" no matter how dramatic the story, it turns out they were actually cheating, because the kind of people who compulsively cheat at games are the same kind of people who compulsively cheat their way through life by twisting reality into these wild narratives that sometimes they actually even believe themselves. Riot giving a bunch of detailed information about how their anti-cheat detected this guy seems implausible, and meaningless since they won't unban him anyway. They have nothing to gain from allegedly explaining all that, and if they're unwilling to unban the person they might as well assume it's still the actual cheater they're talking to, and why bother telling them anything at all?

This all sounds like a load of baloney to me. Plausible, believable baloney, but still baloney.