If he couldn't utilize what he learned to be of any good against Enel, and if no one in the series ever looks back to confirm, sorry but he had as much Haki then as Blueno.
I love Zoro but we have to be real. Zoro's goal in life is to beat a guy who would get on all fours if Kaido ever walked up to him. No, Zoro is not beating him. He probably isn't even cutting him because Kaido being stronger than he was in the past means that surpassing Odeon isn't reliant on that. Let's all just pray that he gets to solo King.