Main reason is that naval war hasn't been important. After sinking the Moskava, neither side has enough ships to do anything. This might change after the end of

Main reason is that naval war hasn't been important. After sinking the Moskava, neither side has enough ships to do anything. This might change after the end of the grain agreement. Ukraine probably doesn't want anti-ship missiles. They would prefer cruise missiles like Storm Shadow for attacking ground targets. They also make their own Neptune anti-ship missile for defense. Plus, Sevastopol is heavily defended, Ukraine has avoided saturation attacks and makes more effective smaller attacks. They have lots of more important targets. Finally, the west doesn't want to escalate the conflict with Russia. Most of the Black Sea Fleet is hiding in Crimea or Russia. If Crimea is too dangerous, they can retreat to Novorossiysk.