Really the only part that made an eyebrow raise was that I hadn't even considered Thanatos as an option. One of my first exposures to the community was original Morenatsu where TappeixTatsuki was one of the most popular ships and original Lagoon Lounge. I figured I couldn't be surprised anymore after a decade but I suppose we never stop learning.
And it's true, Thanatos does have the whole power dynamic thing to work with. Plus he at least seems to like Dave in some way so he has an edge on the mafia pairings there. Though I suppose Jack "likes" Dave too, I just prefer the latter not being harmed. Still, Thanatos will just be one of those "But why though?" moments I guess.
But yeah, to each their own. If someone wants to write a lengthy fic about Dave and David being lonely because Tyson is dead and Carol left, go for it, I won't judge. Questions maybe, but no judge. It's a story with multiple timelines so that really does leave anything open to possibility in terms of fanfic/art. Which is a thing I like. If you can think/imagine it, maybe it happened at least once in some far flung past.