This is specifically not a concern for Starlink, which is in an extremely low orbit. Dead satellites (and any theoretical debris) would deorbit and burn up in less than 5 years. End-of-life satellites are intentionally deorbited immediately.
Additionally, the starlink satellites perform active collision avoidance.
>Additionally, the starlink satellites perform active collision avoidance.
Is that currently true, or a planned feature in the future? IIRC the whole Aeolus kerfluffle happened because someone wasn't paying attention to their pager.