David Lynch's 1984 film radically diverged from the source material, almost to the point of breaking the theme.
The Sci-fi Channel miniseries in 2000 followed the book but was dull-dull-dull. Also, it pronounced all the names wrong which is pretty unforgivable when there's audio of Frank Herbert pronouncing them. It's "har-KO-nan," not "HAR-ka-nen."
The 2021 movie, I walked out of and let Laura finish it on her own. It's during the scene where Duncan IdaBro - who, if we were following the book would have died half an hour earlier in the runtime - goes down fighting. There's a shot where he drives a knife through a Harkonnan shield at full speed where I decided I was done. If you keep the entire sequence about "The slow blade penetrates the shield," then show the fast blade penetrate the shield then your storytelling had failed. This has nothing to do with following the book, or not, and everything to do with following the internal logic of the film. The Duncan IdaBro death fight completely ignores the story logic set up within the film itself.
(And I was triple disappointed because Denis Villeneuve's "Arrival" is one of the best pure S-F films of the last 25 years and his "Blade Runner 2049" was a worthy sequel, so I really thought he'd do well with "Dune.")
2021 Dune needs more Sting, alright. Also more Jurgen Protchnow's Leto (Oscar Isaac is usually entertaining, but his Leto is boring), Patrick Stewart's Guernsey Hallack, pretty much the rest of Lynch's cast. Toto and Brian Eno to write some music that has actual identifiable themes and motifs, Lynch's costume designers who knew to give Atreides, Harkonnans, Sardukar and Fremen distinct looks which could be instantly told apart at a glance, and, basically, just any kind of style at all.
The 1984 film is the least book-accurate adaptation, but it's the best film by far. Much like the 1982 "Conan the Barbarian" film is the best Conan movie despite having backstory, side characters and main plot that resemble nothing written by Robert E. Howard.
The only two things the 2021 Dune did right were 1) cast an actor who could pass for 16 to play the 16 year old Paul (Kyle McLachlan was quite obviously a decade too old), and 2) ok, the ornithopers were really cool.