I didn’t read the books so I may be wrong, but it’s seems like the whole point of the movie is about him being the “chosen one” and him coming to terms with it and believing in himself/trusting his visions kind of like Neo in the matrix
There’s religion all interwoven throughout the film if you pay attention and recognize it so I’d say it’s religion/politics
the clear bad guy is the fat blob looking man. What is he really? He represents evil if Paul is the good in the movie
and does the sand monster have any other/deeper significance or is it just a brainless thing that tries to keep people off the sand