how dare you besmirch the Epstein drive
There are books that are WAYY farther from our current techlevel, like Murderbot Diaries or Ancillary Justice, which handle this much better. I just don't see how adding pseudoscience improves ANYTHING-- better to just gloss over it.
I think it's fine to take scifi tech with a grain of salt; most authors skip the absolute technical details so we just have to assume that things work in some way we don't currently understand. Someone did the calculation for the Epstein and it doesn't look great: http://toughsf.blogspot.com/2019/10/the-expanses-epstein-dri... but only based on the vague technical details provided in the books.
The Jean Le Flambeur trilogy is one of my favourites, it does a LOT of quantum hand-waving but the price is worth it for all of the amazing things in that universe. "This sounds so fucking cool" > "That wouldn't work irl" for good sci-fi imo. As long as they don't mess with thoroughly understood concepts and rely on "things we don't know yet".