As to that counting him above commander level, honestly that depends on how the various yonko commanders stack up on the power scale. Im assuming katakuri is overall one of the strongest amongst all the various yonko commanders, but I could be wrong. If kaidos top guys are stronger than katakuri then I would place luffy firmly commander level. If he beat the number 1 commander amongst the yonko, (And imo could do it again, somewhat easier next time) then I think he deserves to be put somewhere between commander and yonko. He is very much so NOT a yonko level fighter yet. Thats a pretty freaking big gap in power after all. But if he is stronger than the best commander, then he cant really be considered that level either.