It’s not difficult to see what Putins wants...and it’s not about Ukraine....from his perspective it’s the landbridge..and certainly controlled Black Sea for his fleet and access to the Med. Sea.....and if he must landlock Ukraine.
Thing is, he already had access to the Black Sea and the Med after 2014. Not total undisputed control of the Black Sea, but Ukraine was in no position to challenge him on the sea, so for all intents and purposes, if that was his strategic goal, he had accomplished it, and is only risking losing that by waging this war.