Well, so much for KKG destroying Onigashima, let alone Kaido.
The fight was very great; I liked the choreography, especially of how both switched between their modes.
Now it's clear, chapter 923 Kaido legit beat the air out of Bound Man, that was base Kaido. But it seems Luffy learned from his lesson and learned G4 switching by controlling his air inside his muscles better.