If human souls can be claimed by Daedra or Aedra, then where does a dragon soul go?

1st, the souls that a dovahkiin absorbs. I mean, they can't be destroyed right? That would be awful. So where do absorbed dragon souls go if not the worse?

2nd, where does the soul of a dragonborn go? It's a dragon soul if i recall correctly?

3rd...never mind, dragons can only die by the Dragonborn or their father akatosh as far as I know.

Dragons don't die, unless their soul is taken by a Dragonborn, killed by another dragon or Akatosh, then they die. The absorbed souls I guess will be a part of the Dragonborn, of their own soul.
If the Dragonborn dies the dragon souls vanish, and I guess the Dragonborn is reincarnated. Just a theory, I'm not that great with the Lore.