Kizaru is blown away by Luffy's punch (he uses a
normal Haki punch, not a new attack).
The decisions that Eiichiro Oda is making Luffy go through here are quite questionable:
- Snakeman without Conqueror's Haki, and without named attacks.
- Giant Gear 5 grabbing Kizaru with one hand and deciding to throw him when there were several other more most effective ways to do with kizaru simply immobilized in your hand.
- Playing around the entire time in Gear 5, until forced by Franky to do something and only near reaching his limit does he finally use Conqueror's Haki.
- Now he enters Gear 5 and attacks Kizaru with a punch that apparently doesn't even have that bubble effect, and is only coated with basic Armament Haki, when he could have made Luffy use a Conqueror's Haki punch...
- Not restarting his heart when he's in better physical condition than in Wano where he basically had died and suffered more damage.
The interview where Oda states that he simply needs to restrain Luffy because he's too strong is indeed very real.