Russian fleet reconstruction would take decades

How quickly could Russia rebuild its fleet if it retained Crimea and revamped the shipyards after the war?

It would take decades because the shipyards and the wider naval support system require root-and-branch reconstruction.

Territorial control does not instantly recreate shipbuilding capacity or a functioning fleet. A Russian recovery centered on Crimea would take decades because damaged or neglected infrastructure must be restored before new construction can proceed reliably. The problem extends beyond individual slips to the industrial, training, maintenance, and organizational systems behind them. A root-and-branch rebuild means that refitting surviving ships alone cannot solve the deficit. Possessing a naval base is different from having the capacity to generate sustained maritime power.