While anti-ship missiles might push back the Russian blockade, It isn’t difficult to destroy the docks and grain storage facilities in Odessa with a few missile strikes. It may be tit for tat, but tat takes it on the chin.
Tat is a wasting asset if the blockade continues. And the Russians can decide to shoot at them anytime as it is. This is war, not a conversation. But I doubt those dockyards are high priority in the Russian grand scheme of things.
Docks and grain storage facilities are a lot easier to rebuild than warships, especially when most of Russia’s warships were built by Ukraine, prior to the collapse of the Soviet Union, so they can’t currently be replaced.