Zoro is trying to figure out the best way to stabilize his haki to control enma and realize the best way to control enma is for him to release his haki in high levels, not have the sword take it for him.
Zoro using ACoC with demon splitter.
Regardless of what type of BS or headcannon anyone trying to claim, Oda Zoro's ability to use ACoC has nothing to do with enma. He's able to use it freely without needing enma.
Using enma to grow stronger is like training with a weighted vest. You don't have to wear the weighted vest to have the benefits of training with one.