How are you going to get rid on the heat?
And they won't all be in constant unfiltered sunlight some will be in the earth's shadow
And they won't all be in constant unfiltered sunlight some will be in the earth's shadow
They will not be, or need not be, in orbits with substantial amounts of shadowed time.
These satellite will need larger radiators. It's an issue satellite designers have long dealt with, so the presumption that SpaceX has somehow missed the issue in their new design is not credible.