To be somewhat fair, all of Russia’s claims in Ukraine (Crimea, the Donbas) would give them unparalleled access to the Sea of Azov and the northern banks of the Black Sea. Yes, I know they control a significant portion of the Black Sea already, but this would allow them to wrap the Sea of Azov nicely.
I know Russia states they’re there to kick the Nazis out of the Donbas and protect the Russian language minority in that region, but I also don’t believe any nation, especially a very nationalistic, neoliberal government like Russia’s, is out doing something out of the goodness of their hearts. Call me a cynic, but I think the expanded Black Sea control is more important to the government.