So I reposted my original comment content over on the Dark side post, here. And I can't really answer the question about recommending the book without referencing some of the content from that comment. Thing I will say here is that for a book about Phasma it was not nearly enough about or with Phasma. It's, like, told practically third-hand by characters who have reason not to be Team Phasma. Add in what to me were horror elements and... well, if you like horror, I might recommend it, but horror is not my genre. (The, ah, deeply dysfunctional family elements, speaking euphemistically, on the other hand, were something I personally quite liked, as it makes a certain kind of sense for her character.)

I felt like Hux was superfluous and that I would have preferred more screentime for Phasma. I mean, I agree with you about his hateability, I... just didn't need him around as a character.