Zoro is not running away from a fight lol, read the manga
For once put your Zoro bias aside, seriously just fucking do it.
Saying Zoro is not defeating Nusjuro is NOT a fucking downplay on Zoro.
Zoro will still fight Nusjuro but not in this arc, and no Nusjuro not being defeated in this arc doesn't mean that he will be Zoro final opponent.
Also you need to read the manga because it was shown multiple times that the whole point is to escape from Egghead, this arc is not a arc that is meant for fighting like how it was in Wano.
The Gorosei are not mean to be defeated in this arc, Oda is simply teasing us for what will happen in the future for them.
That's the last time I'm going to explain it to you, if you still don't want to accept it then that's on you.