I just watched most of the Alcaraz-Sinner USO match again. I agree with you about Sinner being insanely overrated here. Guy's a massive choker and that usually doesn't change as a player matures (Lendl and Agassi would be two exceptions). Of the players under 25, the only two who aren't chokers are Alcaraz and Rune. They will eventually rise to the top of the game, not chokemeisters like Tsitsipas, Zedrot, Sinner, etc. Med also has choked massively against Nadal in two huge matches.
Just imagine Sinner trying to serve out the Paris final against Novak and saving three BP's in the process. Rune did that a few weeks ago at age 19. Sinner could only dream of such mental fortitude.