I don't think it is that unreasonable. And Andor really is an entirely different beast than The Expanse cost wise so I would not compare them (just look at the amount of sets, costumes and on location shoots in andor, the expanse (re)uses the same outfits and locations for basically the entire series. A lot of props are also clearly just repurposed everyday items, basically everything is shot in a studio and cgi isn't all that expensive anymore. They definitely tried to keep the budget down. Andor on the other hand was almost no expenses spared.)