the navy acts as mobile missile bases, they also allow Russia to move supplies by water, with there only being 2 land routes to most of the front, the ability to use shipping to bypass blockades, the sinking of the Russian fleet would also have allowed Ukrainians to more easily destroy the bridge between Russia and Crimea, this would make 80%+ of Russian positions in Ukraine untenable in terms of holding militarily, and since Putin can’t afford to lose half his army in just a few months he would be forced to pull out and negotiate.
the navy acts as mobile missile bases, they also allow Russia to move supplies by water, with there only being 2 land routes to most of the front, the ability to use shipping to bypass blockades, the sinking of the Russian fleet would also have allowed Ukrainians to more easily destroy the bridge between Russia and Crimea, this would make 80%+ of Russian positions in Ukraine untenable in terms of holding militarily, and since Putin can’t afford to lose half his army in just a few months he would be forced to pull out and negotiate.