In my mind, the Twin Demons path was the most canon, it fit the world building and just felt the best written. JMO of course. Sub content always kind of felt like an "alternate" for fun route, probably that Tess just found fun to make. I don't know if that's true now or not anymore.
For me, DomKane, especially the aforementioned Twin Demons route, was the most "game" like, where I'm making decisions trying to "win" the game.
Meanwhile SubKane is honestly almost entirely the opposite. I make choices to see him and the others fail and laugh at them. I almost think of that route as Olivia's route, since she's the one that then has to take care of everything on her end. When this game is fully complete, I can see a remaster/remake where it is 3 different MCs that you pick at the start, Kane, Olivia or Seth, with the decisions made for the char you pick. But who knows if that would happen or would even work well. With how big this game is getting and it being split, if that were a way to divide it into 3 different self contained parts, it could work out better.
But right now we're still looking for updates and probably far away from any completion of the story. I do expect K1 Kane's story to end soon enough though, and maybe K2 Zack, K3 Jake or something like that. Of the sub routes, K4 Kane and SecretSub Kane seem the most likely to make it to the end.
I also don't expect every Karlsson sister to make it. We know Astrid and Veronica will, but the rest probably don't have that plot armor. At least on some routes some of them likely go.