If you are interested in the naval implications of Sweden and Finland joining NATO, I have an article for your enjoyment. From the CBC (Can.) comes a discussion of the difficulties the Russian navy will have in the event of hostilities with NATO.
Russia has three warmish water ports, that likely don't freeze up in mid-winter. St. Petersburg and Kaliningrad are on the Baltic Sea, and Sevastopol in Crimea is on the Black Sea.
Ingress and egress from both of those seas is now controlled by NATO countries. Between them Sweden and Denmark control the narrow waters giving access from the Baltic to the North Atlantic. And all by itself, Turkey controls the strait connecting the Black Sea to the Mediterranean.
That leaves the Russian navy with Arctic Ocean ports like Murmansk and Archangel, plus Vladivostok on the Sea of Japan. While having unfettered access to the open oceans, none of these is ideal. The Arctic ports freeze up in winter and Vladivostok is something like 9-10 time zones away from most of Russia's population centers.
In wartime, geography matters ... a lot.
