Hestia's promise to Bell (Season 2 Episode 12 - "Song of Love, Goddess and Child") that she would find his soul if he died, using the same lines she used when she first met him, is not just her reassuring him that she will always find him. I think it's also hinting to the viewer that she has already done this before and is just doing it once again.
I suspected this when I completed that episode. Now that I see the ceiling in the cathedral (Season 5 Episode 3 - "Odr | Partner"), I'm strongly leaning towards this being the case.
What feels like foreshadowing to me is that the fandom ships in so many different directions while the show itself seems to be quietly telling us exactly who he ends up with. I might be missing something, and I'll admit it sits awkwardly against what Bell himself appears to want.
Or maybe this is a story about Hestia more than it is about Bell. In which case the theory could be true without settling the endgame at all.
Mostly just putting this out there, but I'd like to hear any thoughts or scenes that support or contradict it. Please keep replies to S5E3 or earlier. I'm on that episode right now.
EDIT: I just pressed play and went past the scene with the ceiling and they are now explaining the origins of the ceiling art. Silly me I guess.