When Luffy left WCI, he was Katakuri level. Now he’s way beyond that level thanks to his new training so he’s already way ahead of the Calamities. Why would he fight them ? Luffy gets warm up fights against characters that are relatively "unimportant", in the sense that they’re never an antagonist’s most valuable assets. Blueno is always used as a reference but that’s the thing, Blueno was the fourth strongest, he wasn’t Jabra or Kaku. And this fight was just an excuse to introduce Luffy’s Gear Second.
I don’t think he needs a big warm up fight against a monster just because he probably won’t get to solo Kaido (which isn’t even confirmed yet). He a got a ton of help against Doflamingo yet he didn’t get any warm up fight against one of his best men, unless you seriously wanna count his fight against Bellamy. Did he defeat Pica ? Trebol ? Heck, even Diamante wasn’t defeated by Luffy and instead just served as a hypetool for a secondary character that won’t have any relevance in the rest of the story.
Kuroobi and Hatchan didn’t serve as warm ups for Luffy. Mr 1 and Mr 2 didn’t serve as warm ups. Ohm and Shura didn’t serve as warm ups, Sattori did yet he didn't even get defeated by Luffy. Kaku and Jabra didn’t serve as warm ups, Blueno did. Hyouzou and Wadatsumi didn’t serve as warm ups. Vergo, Pica, Trebol and Diamante didn’t serve as warm ups.
King and Queen are Kaido’s top 2 men, they‘re not warm up material.
I think this idea of Luffy defeating the strongest or second strongest YC was born because of recency bias and it has to do with Luffy vs Katakuri. It’s true that Luffy defeated BM’s strongest underling but Luffy’s main opponent in WCI was technically Katakuri, not BM. It’s never been BM. And this fight was necessary for Luffy to reach a new level. Now Luffy already surpassed the YC1 benchmark, Commanders have nothing to offer him anymore in terms of progression.