Request for either end of the extremes: a book with the LEAST character arc, or a book with the MOST character arc

I want to read them back to back, to feel the difference it makes. Please help me find the extreme examples!?

And bonus points if they are entertaining books (I like adventure, thrillers, sci fi, fantasy, grief and self discovery, historical fiction. Not such a fan of pure romance)

An entertaining book with book with the flattest characters all around, no growth or learning or change in personality or behavior.

And a book where the characters organically grow and learn and reshape based on the events they experience.

Thanks for reading my plea!