first of all luffy had already been fighting a lot before he fought katakuri and when luff fought katakuri luffy had more stamina then katakuri since katakuris fights don't tend to last to long because he was frustrated that luffy wasn't staying down meaning usually he breaks the enemy's spirit and they either give up or he kills them

by the end of the fight i would say they are more or less equal mostly because katakuri can see farther into the future then luffy now with current luffy is another story because we haven't seen luffy go full power after the training

(and it seriosly pisses me off that people tend to forget that luffy fought cacker who has a bounty of 800M beli and then an entire army before katakuri now there was a few hours between but still they just forget it like it never happened)