For instance you can't disrupt the 2nd law, so at some point it's actually true that it is impossible to mitigate overheating and you won't be able to improve Stefan-Boltzmann law (except for increasing our emissivity, at night I'd guess). You can try to play with mass transfer but more thermal escape is not a good idea and a heat exchanger with extraterrestrial masses won't work.

I know it's hard to take and that physicists sound arrogant when they do this, but that's how it is.