fine, let's not base it off a single game where he won with Black against at 2563 GM Yoo.
What about this post here: https://www.reddit.com/r/chess/comments/xagis6/a_look_at_hans_niemanns_full_results_in_his_last/
A look at Hans Niemann's full results in his last 10 classical tournaments(including the Sinquefield Cup) and performance ratings. In total, he's played 71 games, scoring 48/71(67.6%) against an average opponent rating of 2610, for a performance rating of 2728 FIDE.
Is that enough evidence IF THERE was NO cheating OTB during those 10 tournaments, that Hans is deserving of having an ~2700 FIDE rating?