These satellites will be in orbits where they are always illuminated. That means constant temperatures, which means no thermal cycling and no reliability concerns.
When people say 'running it hot is bad for reliability', they mean 'running it hot and then brining it back to room temp from time to time will eventually kill it'.
It's in space which requires liquid cooling. No rocket is big enough so it has to be assembled on orbit. No liquid cooling terrestrial system is 100% leak free.