Gideon the Ninth by Tamsyn Muir (The Locked Tomb, #1)
Gideon the Ninth is a dizzying blend of deaths, betrayals, reversals, and epiphanies; A necromantic locked-palace murder mystery come struggle for survival. There's a strong aesthetic sense, complicated relationships, and horrifying levels of gore.
This book felt good to read; the blend of occasional older syntax and modern vocabulary made "necromancers in space", er, "necromancers on a desolate planet" feel complete. I love this depiction of magic co-existing with technology in a decidedly-futuristic space. I don't mean to play up the tech too much, it factors in about as much as the existence of elevators does... they're relevant whenever you need to use one. But their presence is a periodic whisper of "we're in the future and there's magic too..." The language has a visceral "crunch to it", which is a style I like.
Because the POV character isn't always up to speed on what's happening, there's a blend of heavy detail and suddenly important knowledge gaps which meant that for a large part of the book I was having trouble tracking what events were important and how everything connected. This is something I have difficulty with normally, so it's not necessarily a fault of the book, but if (like me) you struggle with that, this book might feel confusing for long stretches. However, the last quarter of the book pulled everything together in a satisfying way with enough explanation that as things were resolved I understood why and how they had resolved, even though I'd been having trouble tracking the details earlier. It meant that the ending felt complete, like a real resolution, despite my previous confusion. To me this is a strength of the book, since even if someone read this over a longer period of time than I did, the ending should still feel strong.
Most of the characters have several combinations of names, titles, and nicknames, but they are often used in ways that reinforce their connection back to each person and that made it easier for me to keep track. It made the level of formality in each interaction apparent immediately, even when no body language was described, and that did a lot to set up the tone of each scene in a succinct way.
CW for gore, body horror, death, murder, degenerative illness, major character death.
*Edit to add that if you enjoyed this book but would like to be less confused by the story, you'll probably love The Tiger Flu by Larissa Lai as they share a lot of strengths.