No need for that actually. They will deorbit within a year if left completely dead, and within a couple of month if they have a single button "start deorbiting" that uses the electric propulsion.

But more importantly, their propulsion allows them to launch at a very low orbit. This is a very good method for a constellation as they can see all the early failures (the beginning of the bathtub curve) happen at a very low orbit and reduce the cost of ground testing.

Their orbital debris management strategy is one of the best I have seen.