Herbert was also high on drugs and not in a sound mind when writing Dune: Messiah. The simple fact his he didn't understand his own book when writing it, and clearly went back on Messiah's themes because the rest of the books say Paul and Leto II are justified.

While I'm Duneposting, I'm gonna say something a lot of post-COVID Dune 'fans' don't want to hear: Chani's rewrites in the new Dune movies don't make Paul the bad guy. Nothing about Paul's motivations or the enemies he fights changed, nor did anything about the existential threats mankind faces in the novels for which the Golden Path is necessary. Paul still overthrows a corrupt empire. He's still opposed by degenerate pedophile cannibals. The Fremen people were still oppressed and lead to freedom by Paul. He's objectively a morally righteous hero. The Landsraad refusing to accept his rule necessitates the war, and his slaughter of his enemies is entirely justified. Chani being against this doesn't make her the good guy who recognizes Paul has fallen. It turns her from his strongest supporter in the novels to a bitter malcontent who refuses to accept change and her people's freedom. Who would turn on her lover for her own selfish desires and views rather than embracing the bigger picture like she does in the novels. Villeneuve claimed it made Chani the real hero, but he turned her into a villain. Though honestly, such a character is a perfect role for Zendaya. It fits her personality.