Lion's Song is a skill made to cut what he can not just with raw power though.
That's likely going to be the secret, combining some form of advanced CoA with Lion Song for a technique that allows him to cut Kaido.
I'm surprised Zoro fans don't know that even pre ts there was a difference between a technique Zoro uses for something that's difficult to cut through, and a technique Zoro uses to deliver most power output.
Same with Zoro vs Scabbards. The difference will be made by his skill with the blade and Haki mastery, not simply "MORE POWAH"