I read (listened to) the Gormenghast books earlier this year and it was amazing.
It's incredibly slow and meandering, almost boring at times. But in a kino way.
The descriptions of people, places and things are so richly detailed that the book can dedicate three whole pages to a random hallway niche with a statue in it that the protagonist walks past in one scene and then never sees again. Completely ridiculous but utterly mesmerizing.
Maybe it's just that I have some kind of fetish for improbably-huge sprawling castle complexes (like Lothric Castle in Dark Souls 3)

The closest thing I could compare it to pace-wise is something like The Night Land but much more professional and less repetitive/headache-inducing.