[Ending Spoilers] Question about the ending

Specifically, Verso's ending. I didn't fully understand where they were at the final fight after Verso and Maelle go through that portal. It seemed like the "heart" of the painting. I also don't understand why the little boy was holding the existence of the painting together. I guess it's a part of Verso's soul, that keeps the magic of the painting together. But does that mean that any of the paintings are kept alive by someone who will eventually tire from it, making them all sort of finite?

I don't know how much lore I missed by not finishing every single dungeon, but my big gripe with Verso's ending is that it's meant to be the "good" ending, but still ends with the genocide of an entire world for the sake of one family's grief. Obviously a big theme is that sometimes there are no good options, so I understand that that's intentional, but I'm wondering if I misunderstood something. I know a lot is also left unsaid and to interpretation on purpose.

I do wonder if we will ever find out more about the Painters and the Writers. They've really built an intrigueing universe.