> Not lichess, but Alireza Firouzja (World Rank #3) was banned from chess.com when he was younger.

This has turned into a bit of an urban legend. The automated system flagged him based on both his rapid rise in rating and reports from several verified titled players.

On inspection by a human, he was cleared.

Danny exaggerates when he tells the story cause it's a funny anecdote.

This was also a very old version of the anti-cheat like you mentioned. Personally, part of the reason I prefer chess.com is their much better cheat detection than Lichess.

My understanding is that that was not about his actual play, but instead about his rapid rise in rating.