Have finally read The Devotion of Suspect X (I’m not sure why I say finally - I do feel like I have been trying to read it for a long time but I could not tell you what was getting in my way) and it is astonishingly good. Holmes/Moriarty vibes but entirely different, mildly reminiscent of The Hollow (maybe only in my head). The mystery is innovative but the characters all stay relatable human. I can see why it won so many awards.
I have Malice to read soon, very interested to see if it’s at all similar