When thinking about this from the perspective of rulers and war, Putin is the ultimate mediocre man of our times. He wanted to be the next Great Tsar - Expander of the Realm, forever mentioned in history textbook as the one who put the Russian World together again after Gorbachev let it collapse.
But career spooks like him and his inner silovik circe don't really understand war and, at the same time, don't trust the army enough to actually build it up to strength. And so he started something that he cannot finish.