As far as I understand (I've somehow never seen the movie, need to change that), most of season 1 is their own take on a lot of the movie stuff. But beyond that (and it gets better and better, this is not a diminishing returns thing) it expands and does its own thing I think. As a standalone TV show, which is the only way I can recommend it having not seen the movie, it's extremely good. One of the best sci-fi shows ever imo, it's wild that an iffy channel like SyFy had both this and The Expanse running at once. And the rare show that doesn't just fall into dumber and dumber sci-fi/time travel plot holes as it goes. It all connects back together and makes sense in the end in a satisfying way, and ends well.