In case it's not clear, both of these options are bad.
"Fully demisable" = 29 tons of aluminum per day in the stratosphere/mesosphere just from reentering Starlink sats, ignoring all the rocket bodies required to resupply the constantly-replaced megaconstellation.
And I hope it's obvious why 100 pound pieces of junk dropping from orbit every hour would probably be bad. So hopefully Starlink engineering is better than Crew Dragon trunk engineering?
This is such an incredibly bad situation...