You lost the Battle of the Black Sea to a country without a Navy. The port of Sevastopol is empty and the HQ is still in ruins.
You are right that having the Ukrainians on the shore of the Black Sea is untenable for the Russians. That is why the Russians will be taking Odessa and the entire coast of the Ukraine before all of this is over.
Zeepers are propagandizing morons with micro penises.