still the dude has no blacken blade:
So I cant see him being the true endgame for Zoro which all his postimeskip road is to defeat the only guy that has at current time a blacken blade and is well know to be the strongest swordman in OP
Dressrosa first mini step for Zoro was with coating you should be ashemed if even a scratch is left on the blade
Then Wano further explain that even top tier pirate like Oden coudnt achive the blacken blade even if he had mounstrous haki and coating conqueror (which Zoro got post Wano), yet Oden's dad stated that Zoro will achieve that
I would take the gorosei guy to further expand this road so that when Zoro vs Mihawk finally clash Zoro knows how to get wado ichimonji a blacken blade