I’ve heard that from people who have read the book.
I read the books prior to seeing the film, long prior. I watched the film once, reread Dune and watched the film again. I really enjoyed it at that point. The people with me had no idea what was going on. It’s not easy to watch unless you have some idea what is going on.
Guilty. Although I may not have started reading the books until after I saw the movie.