This is actually a good point.
If Zoro's Onigiri from last chapter wasn't able to really damage Kaido, and that was using Enma.
That means it's not Enma's feat to create such a massive strike in this chapter, that's Zoro's feat. If it was just Enma, Kaido would've been sliced from the first onigiri.
That's it, gg, it's not Enma's power with Oden's Haki or some shit, it's Zoro's.