This is entirely inaccurate.
ISS does not use cryogenics for propulsion. Why? Because cryogenic fuel transfer is crazy hard. Starship cryogenic demonstration was just moving fuel between two tanks in the same vehicle… a trick NASA mastered and surpassed with the Shuttle external tank.
For better or worse, both China and the US view space primarily as a means to demonstrate dominance and prove technological superiority. Antarctica is significantly easier to get to, has way less tactical utility, and seems otherwise irrelevant to the conversation.