Oda is a hack for drawing those "green" flames and haki coming off his blades so early in the fight.
The only thing to deduce from this is Lucci didn't give an opening to end things fast so Zoro dialed his haki back. I mean it's no shocker Zoro does serious damage even prior to green flames and CoC. So the issue was never dealing damage but landing it.
But the issue is this chapter he treated Lucci like a toy, thanks to Sanji's provocation, made it seem like avoiding Lucci and landing was super easy for him....so what gives?
Man Oda fell tf off with fights, he was never elite to begin with but he's all time bad rn.