Go back to Yamato's words about the two of them.
It was very clear to her that Luffy was barely standing, after coming back from a ko to fight again, on the other hand she only started to think Kaido was STARTING to suffer fatigue from seeing his PASSIVE ABILITY weaken SLIGHTLY.
It's a matter of stamina for Luffy, he thrives on long fights, the dude fought Katakuri for 30 minutes with a drilled out stomach and despite being drugged, he was in a worse place here in terms of STAMINA after taking all of that internal damage from Kaido's attacks and his own "sloppy" adv CoC draining him to the point of being completely unable to move unconscious.
yes POTENTIALLY, he would--- beat the Kaido who didn't use his own awakening yet. Luffy thought one more OKG POTENTIALLY would knock Kaido out, 4 more definitely would have the POTENTIAL to knock him out.
To grant "fresh Zoro" feats of fighting Kaido equally, when he cut a distracted unserious Kaido who assumed he didn't have CoC and was focused on trying to kill Luffy as his neck twisted, is completely different.
Barely standing Luffy has proven he can fight on par with drunk Kaido 1vs1, don't try to pretend that isn't true. Note par doesn't necessarily mean 100% equal, but there was a not insignificant CHANCE... if there wasn't Kaido wouldn't be so mad about what happened....