To remove heat by radiation there's a big benefit to running the GPUs hotter as the radiation will be proportional to the fourth power of temperature. This resource is using 85 deg C versus 60 deg C for OP which will improve cooling performance.

If Nvidia/SpaceX can make the chips run at a higher temperature that would help a lot although I assume it would have already been done if it were possible. Another option is to add a heat pump to raise radiator temperature if the smaller radiator mass can pay for the heat pump mass.

Could they run the chips at "normal" temperatures and then heat pump that all into some other mass that lives at "aerospace alloy" temperatures and radiates it away more efficiently?

Sorry but wouldn’t space based DCs need radiation hardened parts which are typically a few generations behind SoTA? Do the centers deploy massive shields to protect the electronics?