Basically looking for dark ambient that can send chills down my spine like someone walked over my grave or otherwise has a certain doom-laden feel to it.

For example, take this track from Subnautica's OST:
https://www.youtube.com/watch?v=57VjILkGVd4

Fucking love that game, and that track will play when you enter certain deeper parts of the map where the water gets murkier just leaving this feeling of uncertainty. Like you don't know what's ahead of you but you're certain it's nothing good.

This Lustmord track also has the feeling I'm looking for.

https://www.youtube.com/watch?v=rVwr-5d4x48

Fittingly, I also picture myself deep underwater when listening to this track (and really the entirety of The Dark Places of the Earth). The ominous echoes just makes me feel like there's some massive predatory leviathan lurking around me in my trek through the dark and it sounds great.

Trying to find stuff like this. Deep ocean theme is optional but appreciated.

I absolutely am not looking for:
-other Lustmord material, I'm already familiar with most of it.
-anything wintry
-drone doom metal
-anything that leans too heavy on industrial influence

Voice of the Stars is cool, it's guitar-oriented funeral doom, there's a cosmic/oceanic vibe to it:
https://arcanevoidsplitter.bandcamp.com ... -the-stars

Deathprod have done a good album too, kind of deep-sea sounding I'd say!
https://www.youtube.com/watch?v=8GXRWfZrf8E&t=934s

Aghast is pretty creepy Dark Ambient.