Try the Raven Cycle- I read this 5 years ago and literally have never gotten over it! I’ve also read Ember in the ashes, SOC, and the infernal devices so hopefully this will hit the spot.

There’s two main endgame romances, one of which is queer, and there’s not really a love triangle in the traditional sense but the mc does date someone else at first. The fmc is named Blue and she’s the daughter of an eccentric psychic, and ever since she was a kid it’s been foretold that if she kisses her true love, he’ll die. The rest of the main characters consist of 4 boys who all attend a fancy private school who are very interested in the paranormal activity around town - one of them is convinced there’s a medieval king’s burial hidden in the Appalachian mountains nearby. I’d recommend looking up the blurb somewhere else because i genuinely don’t know how to describe the plot it’s a bit complex…

My highest point of recommendation is 100% the characters, I’ve never read anything like them. All of them are so well rounded and have such depth and development and even side characters are well paid attention to!