And, like, the literalized metaphor of possession-by-dead-enemy-soldiers is a solid metaphor

That is a solid metaphor. I just agree with you that people who have come through the local equivalent of World War I should have PTSD as well as ghosts.

So I don't know if you would like them, but I read about five books in the mystery series described here, enjoyed all of them as far as the mysteries went, but really enjoyed the fact that as far as I could tell, the books are in fact supernatural and just no one talks about it, including the ghost.