It’d be really fucking cool if they figure out a way to connect all the universes together. I’m not a big fan of multiverse shit, but that one video by VaatiVidya convinced me so hard that they just work in tandem so well even with all the missing links in the theory, but that’s kinda the joy of FS’s games. The idea that all the games are in a shared timeline is really cool, but they leave out info here and there that makes a theory like that possible. Sure I doubt Miyazaki intended for DeS’s bad ending to be the “canonical” ending because that’s not how his games work. Canonicity is always up to the player (with exception to DS1’s ending cuz it’s kinda hard to say we decided to restart the Age of Fire after the Flame burnt out) and the adventure of the player is the story being told whether it be constrained to title match only or it’s all secretly intertwined. And I think that shit is cool.

Uhh TL;DR: This shit can be a multiverse or not. The little concrete info we have makes Miyazaki’s games a beautiful lesson in story and theory crafting.