- They are fighting in a 2 vs 5 which is turning into a 1 vs 5 against an opponent who loves to take hits. So not only it's easier to land hits in a group fight, but it's even easier when facing someone who loves to take hits, and eventhen, we already saw Zoro missing Kaido when he was in his slowest form(dragon form)
- If he landed hits, with Kaido / Big Mom still standing, then it'd mean whatever attack he landed wasn't effective enough