"Traitor Baru Cormorant" by S. Dickinson is a book, and I just got to its finish.
It's about fighting colonization in a fictional world from within a colonizing nation's own organization.
I would say that it's good, but also sad and hard to stomach, on account of folks having no good options within an organization built on subjugation.
@tallbox i had similar thoughts about that book! i did not so far try book two.