The picture clarifies a bit more when you realize Russia’s economy was already going down because of sanctions from the 2014 Crimean invasion. Which they did in direct response to the people of Ukraine rejecting Russia. They wanted to control Ukraine in the first place (like Belarus) because they believe two things. They have a right to a sphere of influence in their “near abroad” and controlling those countries is critical to their self defense. It would be like the US deciding Mexico and Canada must be puppets in order to defend themselves.

So with their economy circling the drain because of their pre-existing beliefs the invasion of Ukraine became an economic imperative. They actually thought it would be like Crimea again. The first wave of troops actually had parade uniforms packed. So the plan was very obviously to use Ukraine’s rising economy to bolster their own and achieve another buffer state.

Now the goal has necessarily changed. It’s survival for Putin and his group. When they failed that embarrassingly they couldn’t back down. They’ve propagandized this as an existential fight for people in Eastern Ukraine who want to be or already are Russian. So they cannot easily give up. This is why Putin keeps saying they control the districts of Donetsk and Luhansk even though they don’t control the entirety of the districts. He’s been messaging for about a year now that he’s willing to end this if they let him keep what he has and don’t object too loudly when he tells his people he got the entirety of both districts.

So basically, Putin realized it was a mistake on the day they had to retreat from Kyiv. Ever since then he’s been furiously looking for an exit that doesn’t involve him being deposed by the oligarchs.