Pretty sure the world series hurts any sort of build up storylines. They barely show up in Galar how are they supposed to build up anything, especially since these stories failed in regions where the focus was in that region. But they're supposed to do it when they aren't even in the region mos of the time?
So this Darkest Day plot showing up now, doesn't mean anything to me
1. We can't be sure of future arcs and what stories they might hold as in non-Galar arcs
2. We can't say there will be a definitive conclusion here, there could be other arcs later on and this is just a massive information dump and action for now since they barely go to Galar to begin with. So in other words, Rose's intentions aren't revealed, Eternatus is stopped by Zacian Zamazenta but flees and isn't caught. And of course there could be some last minute scenes of a potential future arc. And maybe a character can say "I don't think this is completely over with."
Could this be it? Sure this is a world series it wouldn't surprise me they would want to move on especially the opening implying multiple legendary episodes. Since the series isn't JUST Galar but I'd wait to see if this is it, with Eternatus getting caught.
But it does make sense to me why they didn't build this up.
She seemed to be perfectly aware of Lysandre's intentions in the ME special, and then she suddenly has a problem with that?
Knowing someone's goal/intentions is different than knowing how they will acheive it.
You want to save the world.......through genocide.