Him making better use of enma is what helped him achieve koh mode
Zoro wouldn't have that form if he didn't have it
Zoro was able to not get overpowered after he got koh mode unlike before
Yes the problem was figuring out how king's body worked him. Zoro getting koh helped him fight on par and above king. It stopped king from overwhelming and overpowering him
At the same time i don't think coc was necessary to help zoro beat king he could've using his armament alone the same way imo
What says using more Armament will stop King from overpowering him?
Either way, that doesn't really matter much.
The main problem was cutting King and flame off is free game regardless of CoC or CoA.
Ofcourse it won't be 2 / 3 moves, but the job will get done eventually at a higher difficulty.
Especially when King cannot land much on Zoro anyway.