This book is several "how many The Rise of Skywalker loose threads can we explain" under a trenchcoat. 

Some of them work. We have a clear reasoning as to why and how Rey is Palpatine's granddaughter. How a sith dagger with the location of a wayfinder ended up in Pasaana. Why Lando was there. But none of that matters when many of those decisions were wack to begin with, and there's only so much an author could do.

Having both Rey's parents and Lando/Luke looking for them felt like a desperate attempt to patch up two unrelated stories, and Lando's missing daughter is the biggest example of that.

We don't know who her mother is, how she was kidnapped, how Lando felt facing fatherhood. The only reason for that was to explain his involvement on the plot and a throwaway line in a deleted scene of the movie. This is a whole new level of fridging.

All that aside, the book isn't bad at all. We have some quite cool action scenes, and everything that expanded on the dark side was very interesting. But the wobbly reasoning for the whole set up made the entire thing fall flat.

The audiobook narration and production are great though. Absolutely carried the story.