He didn't use haki, not much at least in Pre-TS and in post-TS he never struggled until rooftop.
And on rooftop he used it conservatively because of Enma, his strategy was wrong but Mihawk probably taught him that way.
Nik san...
Zoro unlocked haki against Mr 1 in alabasta. Is that not the official stance of the temple?
So when zoro struggled any time after that, he should have used coc by your own logic.
He didn't
Nope, if Enma was involved in any way with COC, Oden would not be in his 30s without aCOC.
Because lolden was a monster from birth like big meme was.
He was able to appease emma with just his coa alone. So emma never had to suck him.
Zoro himself says that.
lolden was able to use emma since he was 8 years old. he was built different.
Zoro is lacking in coa. That is why Emma resorts to sucking out his dormant coc to satisfy itself
Enma has been specifically stated to draw out Ryo.
If it could draw out aCoC, it would have done so at Zoro's first use because he had no clue about it's nature and the effect.
Ryou is just flow haki
What wano people call Ryou is just haki that can flow. That includes coa and coc.
Regarding others, why Doffy/Katakuri didn't get it - because they arent strong enough to get such ability that only a handful of strongest have. It's portrayal thing - Oda doesn't want them to be that strong.
Lol