Zoro has No Origin or Backstory, why does people keep insisting on waiting for such thing?
His Resemblance to Ryuma or Shimotsuki Family isn't a Hint about his Family, it's a Hint about SHs being Pirates of Fate
Look at Sanji for example, we've already seen him in Two Flashbacks & yet in Wano, what do we hear? Sanji has Flames similar to Lunarians
You think there is a Third Flashback incoming or he has another Family? Ofc not
The idea is that certain things are being passed down, just like DFs go from one to another after Death, just like Haoshoku Haki is only inherited by select few, just like Vegapunk was born Smart, just like Big Mom was born a Monster, just like Poseidon, just like Momo, just like Nami being able to predict weather or Usopp prophesizing the future or Jinbe talking to Fish that no other Fishman can ... etc
Fate is at the center of all these Sub-Plots, something or someone selected all these Characters for a particular Role
Shimotsuki Family Sub-Plot isn't a Wano Arc Mystery, it's a Major Reveal for entire World Lore, not just Wano
Take Big Mom as an example, is She an Ancient Giant? Ofc not, but she clearly inherited Oars Strength (Oda made it fully clear when he made her act exactly as those Kids in Punk Hazard & then Law revealed that WG have always researched how to create Ancient Giants)
The same thing with Zoro, he is just a Kid from Normal Irrelevant Family, but he was chosen by Fate to finish what Shimotsuki Family always wanted, it's basically concept of "Inherited Will"