Yeeeeep thats my favourite genre and possession is one of my favourites.
I think I've got a few decent recommendations for you.
- Rosemary's Baby
- Hereditary (or anything by Ari Aster)
- It Follows
- Werckmeister Harmonies
- The Lighthouse (or anything by Robert Eggers)
- The Wickerman
- Get Out (or anything by Jordan Peele)
- The Thing
- The Babadook
- Suspiria
- The Killing of a Sacred Deer
I think they're all less bizarre in comparison to possession but fill that psychological horror hole for me.
The more important part for me is that they rely on deep psychological horror and not jumpscares.
This is a fun little list on letterboxd and you might find some stuff you like here too.
Psychosexual dramas, nihilistic fever dreams & surrealism with a touch of humour https://boxd.it/2Qq4Q
That started off as such a promising joke