9M vs 8M is miniscule. Kuroobi was at best slightly stronger than Hatchan.
As for Zoro facing commanders Post Wano, who said they push him to high or extreme difficulty.
Postskip Zoro has been much stronger than all the opponents he defeated. Barring Mihawk and Borsalino, there's no guarantee that any of Zoro's other opponents can push him to solid high difficulty let alone extreme.
Shiryuu has the best shot, and even then he may well get mid diffed.
As for the rest of your comment:
- Zoro wouldn't top his Rooftop feats in Elbaf or against the Blackbeard Pirates.
- EOS Sanji will not defeat an Admiral.
- Beating a BB commander is not impressive in the slightest, Nami and Usopp are going to do that.
- Sanji can't even beat Shattered Bones Zoro let alone healthy Zoro.
- A healthy Zoro low diffs.