> So, not saying that it’s easy or feasible, but saying that cooling then seems “just” as difficult as power, not insurmountably more difficult

This is with an ideal radiator and perfect pointing so it receives no incident light, so in practice you need a bigger one than this.

However, if you think launching a solar panel that is the size of 10 NYC city blocks is "manageable," then why not throw in a radiator that is about 15 city blocks in size?