Kin got hit once by Doflamingo, who caught him off-guard while he was dealing with Law's wounds. Kaido has been hit once by Kin, who caught him in a surprise attack. Even the strongest fighters can still take a hit if they're properly distracted.
All this powerlevel stuff is dumb in general but this is a particularly bad take.
For once, I agree with you, your take is very bad.