Average life of starlink satellite is around 4-5 years
A better orbit might be Sun Synchronous (SSO) which is around 705 km, still not "deep space" but reachable for maintenance or short life deorbit if that's the plan. https://science.nasa.gov/earth/earth-observatory/catalog-of-...
And of course there are the LaGrange points which have no reason to deorbit, just keep using the old ones and adding newer.