Shiryu will be Nothing and Zoro will have to unlock the ability to cut Nothing
In One Piece Fighting Path we have just seen Mihawk cutting through dimension, with Shiryu something similar will be required. It’s a pretty broken ability
Yes, a void body is a perfect counter to Zoro's insane firepower...
...however, I think Shiryu will have to do much better than that to be, possibly, Zoro's most significant fight in the show, after Mihawk.
Offensive capabilities are also required, something that will make Zoro struggle, instead of hax defensive abilities, which most Zoro's opponents had in the past.
There has been no parallel to Kaku's fight in the post-TS, something that will make Zoro struggle in CQC, even turn out superior to Santoryu... That's where I think Shiryu's Orochified Raiu will come in, basically 8-sword style, 2x of Kaku's Yontoryu...
While it is not excluded that Mihawk might also have a superior style, at least through some techniques, despite wielding a single blade, I dont think that will be the focus of the fight but instead the supreme Haki and possibly overcoming death, an impossible challenge.