At first the aim was to overthrow the Western-oriented government and install a puppet government in Ukraine. Then he realized Ukrainians didn't actually want t

At first the aim was to overthrow the Western-oriented government and install a puppet government in Ukraine. Then he realized Ukrainians didn't actually want that and were willing and able to fight back. So now he's basically looking for anything he can reasonably sell as a success to his own populace to be able to end the war as soon as possible. Annexing more of Ukraine, especially the Donbass, is one such thing. The problem is that Ukraine isn't just going to roll with that, plus sanctions will only increase, again leading to further economic decline. He really can't win anymore. Only face-saving options are becoming a second Iran / North Korea, or a Chinese vassal.