I’d love to recommend the tyrant philosophers trilogy by Adrian Tchaikovsky! It’s such a deep and interesting discussion of colonialism, taking place in a fantasy country that had been relatively recently subjugated but also had been oppressing another country and it handled it really well!

**These books must have a strong critical lens and not just have colonization in the story.

For example: The Will of the Many technically has colonization, but it's just a part of the plot/world building and there isn't really a strong critique focus in the book; unlike in Babel which explores the long reaching ramifications of a colonial empire, and seeks to revolt against these norms.