Ehhhh, idk, I'm not formally part of any fandom, I just yap about it online when the opportunity arises, but I'd probably say Dune? And this is not very controversial amongst book readers (most of the current fandom came from Denis' movies) but the recent movies both left many important book passages/scenes out (the dinner party, for example) and also unnecessarily and to the movies' detriment changed some characters in very fundamental ways. And I'm not even talking about sex/gender cause sometimes that doesn't change much of the narrative, but other stuff like Chani being just a sassy New Yorker instead of an extremely mature 15 yo with big responsibilities in her tribe, or the superficial "religious schism" subplot in the second movie, which is certainly relatable/acceptable to the average Western 20 something but is incompatible with Fremen society as Herbert wrote it.

Instead, Denis made a very pretty movie with long, silent shots... but Dune is anything but silent, it's heavy in dialogue and internal monologues like Legend of the Galactic Heroes. A bit of a disappointment but, hey, the first movie pushed me to get a COVID vaccine shot quickly so I guess something good came out of it? 😅