EOS Luffy will surpass the OG Joy Boy.
Saying Kaido wasn't 100% prime is pure head canon. Saying he could've been stronger if he was XXX years younger or whatever is also pure, baseless head canon. He was the strongest he has ever been and ever could be in Wano. There was no accompanying statement that clearly stated that he wasn't the best he could be, as was the case for Old Whitebeard in Marineford and Garp in Fullalead. They all had accompanying statements. Saying Big Mom wasn't in her prime is also baseless head canon. There is nothing stated anywhere that her age had somehow weakened her or that she wasn't stronger when she was younger. The age is meaningless. Imu is probably 800 years old and the majority of the Gorosei and the gods knight are old men. Akainu is in his 50s. The only one reason we its agreeable for Whitebeard is because its flat out stated for him multiple times that when he was younger, he was stronger, that his age, his sickness etc etc all handicapped him. No such thing for Kaido or Big Mom. Saying if Kaido was 10 years younger, he could've been stronger is also baseless head canon. Especially because everything we've known about him when he was younger is the opposite, almost died to Oden, cheap shotted Oden, fought Moria, cabin boy of the Rocks pirates etc etc. The version of Kaido we saw in Wano was the strongest he could've been.
1. Saying Kaido was not 100% prime or his age somehow nerfed him is baseless head canon.
2. Heck, the idea that he could coat his hybrid form with the flame clouds in the first place is baseless head canon. Its giving him a random powerup he has no canonical basis for to make him stronger.
3. Lmfao Kaido isn't getting any close to high-mid diff against EOS Luffy. He gets low/no diffed by EOS Luffy. Even if we assume he doesn't surpass OG Joy Boy (which he very likely will), he absolute destroys Kaido. Heck, EOS Luffy would high-mid diffs Big Mom + Kaido in a 1v2. Idk how anybody can say that shit is even close after we saw saw OG JB literally neg diff wifi haki diff somebody with Kaidos durability + very likely conquerors coating (possibly stronger then that of Kaido) along with 3 other gorosei, another, like Nusjuro probably being stronger then Mihawk on top, and he did this shit 800 years after he death, also Imu's PTSD scream is enough to tell us how much of a menace OG Joy boy was and how much of a menace EOS Luffy will be. Kaido is no where in this ball park. At all. Old gen in their prime ain't either. Kaido gets obliterated in a 1v1 against OG Joy Boy/EOS Luffy. It ain't close at all. Kaido ran from Shanks in MF, reps him and clearly is at a minimum equal (more likely stronger) then him. And OG JB Haki 800 yearas after his death>Shanks haki. Now combine the strongest haki we've ever seen + unlimited G5 and complete mastery over his abilities and Kaido is lucky if he doesn't get 1 tapped. Nah, G5 Luffy is already above Kaido. Their hakis are already equal as confirmed by the skysplit. The only reason Luffy suffered those previous defeats its because he didn't have the abilities he had now. It wouldn't be taken into account now. If Luffy played his cards right and doesn't immediately spam G5, he bodies Kaido. We've seen he can hang with Kaido for a good long while just base, we know he doesn't experience side effects of G4 now, if his smart, plays his card rights and sticks to G4 + ACOC and only uses G5 at the end, doesn't forget that he clearly has some kind of self-revive ability with the drums. He would be able to defeat Kaido.