You're memeing, right?
"The only stupid logic would be to outright ignore the author's masterful portrayal that has Mihawk confirmed above Shanks "
That's like, meme levels of argument.
Mihawk's sword was passed down from master to student for generations, and over countless masters, it had busoshoku hardening used on it so many times, that it became a black blade. The reason why roger's sword wasn't a black blade is because it wasn't passed on from generation to generation. The reason why whitebeard's naginata wasn't, is because he was arguably the first one to have it, etc etc.
Considering all these weapons have been around for generations, the burden of proof is on you to prove mihawk was the one who turned it black, and also to prove that it had nothing to do with the blood, sweat, and tears of those who held the sword prior.
Since that's functionally impossible to prove, the basis of fact till we are proven otherwise, is my stance, if you can't handle that, then you can't handle facts, and I suggest you take a break from the internet and find a nice corner to cry in.