The Expanse - and we can think of the novels too here, not just the telly show - is more of a hard sci-fi, which means generally stick to legit science beyond the fiction.
One grave mistake: belters live in micro-gravity and through the generations they got sensitive to gravity, they even tortured by Earth 1G.
But then how can they stand the acceleration/deceleration of their spaceships with their way more - way more - gravitational pull than the pleasant Earthly 1. They could do stuff in space, but flying around with Epstein drive should not be in their skillset. Or in their lives at all. Unless they want flat and crushed belters.