The actual goal of Putin is to do what Bismark did in 1860-70. Bismark used military force to achieve mind-blowing gains. Not only did Prussia conquer a number of territories from Denmark, Austria and France, but the other German states decided it's a good time to join the "Union", and so modern Germany was created. Before Bismark came to power, Prussia was the weakest of the 5 European Great Powers. When he left, it was by far the strongest.
Putin's Russia right now is less than 150 million people. The rest of the former Soviet states have about as much together. If he conquers Ukraine, then most of them will decide it's time to get back to the "Federation", if they know what's good for them (the exception would be the three Baltic states which are NATO members).
If Putin's gambit works out, he reconstitutes the Soviet Union (itself the reconstitution of the Tsarist Empire), and makes a country of close to 300 million people. For you and me the population is not a very relevant number, but for him it's the number of potential soldiers that he can use to bully Europe.