I don’t have any literary meaning or explanation here, but I had the same experience with it at first. I started getting bored with it I’d say 3/4s of the way in. I’d gotten past all the main plot points and was part of the way through the beginning of their road trip. It just became a slog. So while I don’t know if I liked it or not, I certainly couldn’t put it down. I hate read the last quarter just to get it finished. I’m glad I pushed myself through it. Would recommend it to people for sure, maybe not with enthusiasm though.