I am confident Zoro could split the sky now, he just needs to have an opponent who has AdCoC too.
Kaido knew Luffy has CoC. He still believed Luffy won't be able to unlock AdCoC. Kaido's reaction would be very different if Zoro hit him with AdCoC. You are clearly wrong here.
Zoro cut Kaido with a shitty tatsumaki.
That tells us Zoro's non-CoC asura is good enough to put a permanent scar on Kaido.
A dragon damnation would have fucked Kaido up, let alone CoC imbued Asura.