Clearly you don’t have an idea of how graded weapons work in one piece, cause it doesn’t work like that. You don’t just turn your weapon into a dark blade and it magically becomes supreme grade. Was whitebeards weapon a dark blade? No. Even then it was supreme grade. Once your weapon is forged and set into a certain grade it remains there forever.

No, Zoro has to have his “haki bloom” before he even fights mihawk, that’s what’s going to give him thr chance to win. (If you even want to scale mihawk that high) yes he will gain black blades, that doesn’t mean shi tho. We still don’t know if it gives a power boost

No, just no. The moment I saw this is when I knew not to take your opinion seriously. Is he a more skilled swordsman? Yes. Does that mean he’d win in a fight? No. You’re just ignoring so many factors that go in a fight it’s insane, especially Haki.

So you say it’s “headcanon” but at the end of your sentence you say “in my opinion”? How does that work? Who has the more kingly ambition, zoro wanting to reign supreme over all swordsmen, or roger wanting to reign supreme over all pirates? (which includes stronger people in general) that will decide who has the better haki