The Tillerman Cycle by Cynthia Voigt. It peaked around book three: A Solitary Blue. We were forced to read that in high school and it's the third book and is missing a lot of context without reading the first two. I kept going but the rest of the books were really bad. I finished the final one earlier this year and it was a huge letdown. I also finished reading all the Dune books last year. Everyone told me 5&6 were not that great, but I wanted to read them anyway for completeness. I'm glad I got through them, but they're really not good. The entire series gets a little jarring after the first book because Herbert's characters are not really human. They all think and act on these deeply complex and super human political levels, so they become less and less relatable as you keep reading. I only read the 6 main books. I doubt I'll ever read all the ones by other authors.