As for The Expanse, the linked page rates it as a 4:
One Big Lie: The author invents one (or, at most, a very few) counterfactual physical laws and writes a story that explores the implications of these principles. Consider, for instance, Cities in Flight’s “Dirac Equations” and “spindizzy motor” leading to instantaneous communication, or Mass Effect’s “Element Zero” being the basis for all of the series’ futuristic technology. Other works in this class include The Expanse series, the Ad Astra board games, Robert A. Heinlein’s Farnham’s Freehold, and many of Vernor Vinge’s books.
As for The Expanse, the linked page rates it as a 4:
Gotta love TVtropes.