SOLVED. Fantasy Series with Black Cover, Purple Flower/Flame?? And Female Protagonist

[Alycia]

Hi there, me again, back again with an old series I remember little about.
I loved this one so much which is why I'm so disappointed I can't remember it.
The whole series had similar covers like they're almost Twilight-Esque, completely black with some kind of purply-image on the front.
I can only remember the plot in fragments, and I'm almost certain it was a female author.
Came out probably around 5 years ago, I saw it in a Big W and bought it on kindle but I can't access my account!:((
Female protagonist, the big baddie is like the King, he gives off rapey vibes in my head, I know the books were way above my age level there were like intimate scenes in this. There's definitely a scene with her and him in a big castle somewhere.
She has some kind of plant magic?? With like these giant venus fly trap like purple plants? Maybe they eat people? I'm so unsure, I'll never find them at this rate.
She was in and out of a romantic relationship with one of the other characters, mostly because they had different adventures, he would go off traversing somewhere else while we followed her story and then come back later.
At one point her like, group of people hiked through these giant cold mountains? And slept in caves and things. It was like an epic fantasy that wasn't really cared about but it was so good!
If you know what this is I cannot explain to you how eternally grateful I will be! xx

[Alycia]

bro so i just found it on a whim under strong female led fantasy so if you also wanna know what this is it's called poison study by maria v snyder!!

[Becca]

Here's a list of books with Covers Capitalizing on the Twilight Phenomena - is it any of those?