Possibly the planet has considerably less inhabitable landmass than Earth? Which would make sense, given the name.
It would! Maybe a single continent a bit smaller than Asia/China plus largeish chunks of its surroundings? So the continent of Haixing would be a bit smaller than Russia, area-wise. I really should rewatch the opening narration and see what sort of planet model they used – IIRC it wasn't the Earth.