Thats also headcanons. We can't even assume if his attack would one shot King or Queen, since 1vs1 fights have a build up where both characters are pretty weakened, thats when one of them manages to land their best attack to completely knock out the opponent, King and Queen are tough AS HELL.
If you consider holding a attack that would kill you for 1 second then getting packed up in a cross by Sanji and leaving a meeh scar on Kaido with your strongest attack as something much more relevant than beating a Commander and fighting Admirals, then Sanji is definitely not doing it. Whats the point of Sanji doing that if beating a 1.32Bi Commander and fighting Admirals is even better? Is Sanji supposed to be stronger than Zoro and have better strength feats so?
It's clear that Luffy's CoC punches had more impact on Kaido than Zoro's strongest attack with Enma. And yet he didn't leave a scar on him, same as any other character that fought Kaido except Oden with Enma.
The strength development from a 1vs1 against a skilled Commander isn't to be ignored, Luffy's Future Sight is having a pretty relevant part on his overall strength and feats against Kaido, and thats thanks to his fight against Katakuri, he also could go further with his Gear 4 and develop a new form. Thats what Zoro is needing, leaving scars that doesn't even bring your opponent to the ground matters absolutely nothing but something much more symbolic.
You guys feed yourself with tons of headcanons then get disappointed for no reason