You can miss a place while knowing you became better after leaving it.

Leaving a place that was bad for you does not delete what was good in it, and the missing is not a sign you were wrong to go. You can grieve the friendships, the streets, the particular light, and still be clear that staying would have cost you something important. Both things are allowed to be true at once.

If you feel guilt for missing somewhere you needed to leave, let the two feelings coexist rather than resolving them. Missing is not the same as regret. It is just an honest account of what was there.