I’ve been on a cosmic horror kick lately, and what I’d really like to read is stories or novels of the awful and unfathomable on a spaceship. Stories where we go to them, poke what shouldn’t be poked, scan what shouldn’t be scanned, and things proceed from there.
I read the post and was about to reply with this but you beat me to it.
As for horrors, the short story “Nightingale” in “Galactic North” is probably exactly what they want but some familiarity with the world building makes it hit harder.