Katakuri, the weakest YC1, was still stronger than post WCI Luffy.
Katakuri utterly dominated g2/g3 Luffy
If it weren't for the plot armor here, Luffy would have died then and there. Katakuri should have finished him then.
I am not even sure if Luffy will manage to go G4.
Katakuri toyed with Boundman the moment he got his composure back.
No PIS involved so forget about Katakuri stabbing himself, or suddenly letting go of Mogura.
He won't be doing this. He won't allow Luffy to power up like he did earlier, he won't allow Luffy to just lay down on the floor.
It took Katakuri a few seconds to get adjusted to snakeman and counter it
Katakuri then dances around Snakeman attacks, manages to hit Luffy and put him down first
Even with FS, Luffy loses against Katakuri.
The difference is that Luffy due to infrequent FS will evade some more hits and push the fight a bit further. It basically went from a low/mid diff to a mid/high diff win for Katakuri.