Boldly go.
Why it is hard sci-fi
Soft on the physics, careful about the institutional setting. The shows central science claim is the spore drive, a network of mycelial connections that extend across all space and time and that the ship can ride. The shows discipline is in its commitment to the spore drive as a working biological engine and to its consequences. The show also engages with a Mirror Universe arc that treats the parallel universe as a real political problem rather than a curiosity.
Science inside it
A mycelial network as a fictional but coherent transit substrate, a tardigrade-derived navigator as the original protocol, the engineering shape of a starship that can fold space through a biological connection, and a recurring engagement with the institutional response to a single-case capability that no other ship has.