Kidd isnt below zoro, obviously and this is specialy told by portrayal. Oda uses every chance to display Kid as rival to Luffy since SA. He did in SA, he did bounty-wise, he did in new world, he did in Udon, he did on the see and he does in Onigashima the whole time. Also both presented their CoC early to Kaido.
Zoro just came up with it now. This was his peak this arc and it was enourmous. Now, he has to learn to deal with hit, maybe he will train this with Luffy after Wano. And in his next main fight, next Arc, he will fully use it. I am absolutely sure about that. But for now, he is taken down. Luffy is now fighting Kaido and taking him out at the end. And Kidd is fighting Killer for now and taking her out.