1st person POV thriller books with dark ambience, good prose, and complex characters?

Hi guys. I'm looking for novel recommendations that are suspenseful, thrilling, dark, and atmospheric while at the same time being well-written, written in the first person (important), and with complex characters. I'm a huge sucker for the money-strapped middle-class crumbling marriage trope. I also really like sci-fi-ish horror twists.

So, stuff like Strange Bodies by Marcel Theroux and Lunar Park by Bret Easton Ellis. I also liked the Secret History by Donna Tartt but would prefer something with a little stronger of a personality in an MC than Richard possessed, and he wasn't very active in the plot. The stakes in that book were also really low to me (until the murder) since they were a bunch of rich kids with seemingly infinite money.

Also if it helps, I also really loved Seasons 1 and 4 of True Detective (I read his novel Galveston already), the Night of, and, strangely, horror games like Outlast/Outlast 2 and Alan Wake if you guys have heard of them??

I understand this is a very hyper-specific request lol. And I made a concerted effort to get into Stephen King's 1st POV books but for some reason the novels of his I tried to read were so focussed on action in the present and useless details that I found them slogging-on and unbearable (just my opinion). That being said, I haven't read them all so I would still appreciate suggestions if you have them! Also I'll look into everything you guys suggest anyway so feel free to throw me whatever your gut tells you I might like.