I think Zoro's true purpose and dream of living is YET to be revealed, it will be something BEYOND becoming WSS
There's no mystery here. Like mshbe you don't understand it but there's no mystery.
I broke it down a while ago here;
https://worstgen.alwaysdata.net/forum/threads/zoros-dream-in-spite-of-his-character.5128/
In summary, Zoro's dream is pure unadulterated Ambition. It's Ambition for the sake of ambition. That's why Mihawk exists. He's the end goal result of "ambition for the sake of ambition". You end up a bored strong guy with no real friends or ideals just waiting to die. And then Oda added contradictions to this. Oda made zoro think about why he strives for ambition as it is. Hence all of Zoro's greatest character moments are born from his re-interpretation of his own dream.
Zoro ends up choosing that a promise to Kuina is as great as his ambition when striving for WSS. There's no rule that says you must have a dead friend to be a candidate for WSS. Zoro chose that for himself. Yet it doesn't actually matter. All that really matters is Ambition. You just have to want it bad enough. Because all you get is a sense of accomplishment in the end.
For a detailed breakdown of this across the whole of pre time skip, follow the link above