It just occurred to me - that’s probably it for even a small sneak peek into Zoro’s biggest secrets.
Missing eye, the Grim Reaper, or curse-related stuff.
I had a tiny hope that, with Zoro mastering Haki, Oda would touch upon one of those things.
It turns out not.

This is one of the biggest reasons I'm still pushing Wano Act 4.
Oda refuses to address Zoro and Tashigi's pasts directly, only teases info in SBS's.
We know Japan's obsessions with eye shit from Naruto, Zoro has a mysterious sealed eye.
I was really hoping Sommers would get Zoro talking about his family. Oh well.
The Grim Reaper and Wano's death focus. Perona being Zoro's Mihawk companion, with the "Ghosts of Wano" being such a big motif, and Perona likely being Toko's relative Moria adopted after losing to Kaido. Perona is from Wano, and we haven't addressed this at all.
It's possible Oda splits the Straw Hats up like the Blackbeard Pirates operate separately (Kuma could easily do this), and Zoro, Franky, and Robin are the only ones in Act 4, but I think it's unlikely, especially when Luffy made a big point of stating they'd come whenever enemies showed up.
Zoro's full character will be explored in the next arc, the Pluton War, Wano Act 4.