Yeah, and still Kaido took a weaker G5 advCoC punch and was on his ass.
Kaido took other, much weaker punches before, yes, but a handful of G5's techniques were enough to finish the battle. And Kaido is the tankiest of all.
I can't see what is the problem here: Kizaru took one of the strongest G5 techniques and was supposed to shrug it off when even Kaido did shrug off the weaker ones?