Agree about Frank's later Dune novels not measuring up to the first three. As for his son's novels co-written with Kevin J. Anderson, I gave them another try, but it sits on a shelf today, unfinished. I need to put it in my box meant for the next trip to Half-Price Books. I do most of my reading these days on a Kindle, with the occasional visit to Book People here in Austin for a hardcover or trade paperback. It's a terrific independent book store, one of the best in the country. Like Waterloo Records, a remnant of earlier Austin days that's still with us. As for Kevin Anderson, he's an author who seems to specialize in writing novels based on highly successful earlier novels (Herbert's Dune the obvious example), films (Star Wars, of course), and also TV series (like X-Files). He's pretty good at his craft and has found a lucrative niche, which is not easy to do. @Xerobull described him as Brian Herbert's "ghost writer" for the Dune novels, and he's likely close to being on target with that, in my opinion.
All the other Dune attemps through the years failed. The agreement was Villeneuve would get 2 1/2 hours and 165 million to make his version. The compromise was a Part I. If it made a profit, the studio would grant him Part II. It turned out very successful even before the world premiere. Part I was completed in 2020 but waited a year because of the Covid nonsense to ensure it would get the best presentation possible. It was made for theature release, not for people's crappy soundbars and mediocre walmart tvs. Part I was successful enough to get a Part III which will cover book 2. If the sisterhood is successful, expect a full 3 trilogy series like Starwars along with several spinoffs.