Put a radiator in the shadow of the satellite. The radiator size needed is similar to the solar panel size. Look at the International Space Station; the solar panels are larger than the radiators, and the occupants are far more heat sensitive than semiconductors. The hotter the radiator, the better it radiates.
What's even the point of making this kind of thought-terminating, smooth-brained quip? Do you actually feel it passes for some sort of clever gotcha?
I can exhaustively list the reasons why Musk is an abhorrent leader and human being, but I'm pretty sure you know them all already. Whatever intelligence the man may have once had has long been flushed down the Twitter toilet, as evident from even a cursory look at his social media feed.
It is much more difficult than that. Starlink is essentially IT infrastructure, which certainly produces heat but nothing on the level of pure compute. Ejecting heat in space is a difficult problem that is currently solved on the ISS with large IR radiators which take up weight and space. The size, weight, power, cost tradeoffs lean heavily in favor of ground-based compute.
The ISS dedicates more space to solar panels than radiators, despite the occupants having a very tight temperature requirement, which is about 20% cooler than the max most semiconductors can indefinitely run at. Just putting the radiator on the surface of the satellite might be enough, without even needing a panel.
Even if a heat radiator as large as a solar panel is needed, it'd be only a small portion of the overall cost.
Radiating waste heat on earth is a much more substantial portion of the total cost, especially so considering the social backlash it creates.