I love dark music and music doesn’t really get much darker than her music.
Yeah, very tough to listen to and reading the lyrics along with the music, damn.
If we're going with albums that are emotionally heavy (while musically "soft"), then these come to mind:
The first 3 are all about the death of a closed person to the artists (mother, wife, and son respectively). The last one is
The Caretaker Everywhere at the End of Time, 6 discs about each stage of dementia. I love it, but a friend of mine can't listen to it because it sends them on an emotional wreckage, an existential despair.