In all seriousness, my mom kept buying me their books, and I read them. I read that first prequel trilogy. I read that Butlerian Jihad trilogy. I read the series conclusion.
All of it was shit. Allll of it. Even my young brain knew, reading that prequel trilogy, that they kept getting shit wrong. I mean, Gaius Helen Mohiam is Jessica's real mother? By a rape, no less? Kynes, the Emperor's planetary ecologist went native--because he grew up on Dune among the Fremen? A rich young dude becomes a cyborg? A freaking cyborg! The Harkonnens have a no-ship????? A FUCKING NO-SHIP!
Then we had The Butlerian Jihad trilogy AKA The Terminator iiiiinnn spaaaaaaaace. Which then became the conclusion to the whole series.
If those two jokers ever had actual Frank Herbert notes, they must have pissed and shat all over them, wiped their asses with them, tossed them in a fire, inhaled the smoke, then sat down to write their Dune books.