Sanji....
Strongest move barely hurt Luffy.
But for his favour, Kaido needed very higher end moves to hurt and damage Luffy...
Luffy endurance/durability in G5 is something else, only sword cuts are probably his weakeness so far based on Kaido words.
Even if we go by Kaido words that shit don't even matter cause luffy was tanking those same slicing attacks in G5 without haki .
Not even one slice attack but many and kaido could not even get him to let go with those types of attacks , luffy in G5 is a fucking durability monster .
If people read that kaido fight , the man was getting hit by all type of powerful moves and coming back for more without issues.