Putin's move here is like what you do when your character is about to die in CK3 so you just throw all your armies at a neighboring territory while you still have a claim you can press, even if your casus belli isn't accepted by the neighbors.
The strongest reason for me to believe his thinking is rational in terms of the Russian interest is that there is very little that could make Russia worse after his rule, and there are many reasons to suspect he's facing his own mortality. So here he's making a high-price choice which will dent his bank account and possibly his short-term popularity. As the richest man in the world and the most popular man in Russia, he must be dying and trying to make one last push. Otherwise there's no reason for him not to rest on his laurels: His massive wealth and the total ownership of Russia he has already. The man should retire. But he wants to make himself Peter the Great or Ivan the Terrible; to put himself into the annals of the Orthodox Church, he must conquer the cradle of the Rus'.
My theory on Putin is that he may be suffering from cancer. It would explain his terror of close contact with people, and this extreme move --
My fear about him is that he may want to take the rest of the world with him when he dies, including Russia.
I kinda feel bad for him, he must live a rather unhappy life.
https://www.dailykos.com/stories/2017/9/10/1697580/-Back-in-...
I've met little "non-political" Russians like Putin playing guitar, working illegally at restaurants; accidentally overstayed a visa, have to go home to visit Moscow; you know because there's a soviet pin inside the jacket. Yuri Gagarin, or something. He's one of a type that exists and travels around Europe now.
[Edit: I saw this article had never been posted on HN so I just put it up... but it's been immediately deleted, for reasons I don't know].
Wasn't it hilarious how in 2008-2012 (? or thereabouts) the Prime Minister was suddenly more important than the President, when before and after it's been the other way around?