Luffy's 1v1 fight against an actual Yonko has yet to commence.
Celebrating a little prematurely there aren't you? Just like when Zoro cut Pica in half and yall lost your minds that Luffy would never top it, and Oda said "Hold my beer" and folded a city in half with Doflamingo's body.
So let me ask you. Is defeating King not worthy enough for Kaido to consider Zoro a monstrous Samurai? King too scrubby for that?