There has been, for some time, attempts at coming up with schemes to refuel satellites. So far, this hasn't led to anything successful; the orbital mechanics of the situation is pretty daunting.
But for a Starlink specific solution, it could make sense to design supply modules that a Starlink satellite rendezvous with to get more propellant and/or a new payload comms package.
No need to return stuff to Earth, just receiving supplies/upgrades.