There are many partial answers to Joe's original question.
1) Rumours abound going back to 2020 that Putin is terminally ill with cancer. His recent "strangely fat face" may be a result of steroids used in cancer treatment. If this is true, and given his fixation on the "Ukraine Problem" (that he recently wrote a book about), many believe he wants to leave a legacy for Russia before he dies by bringing it back into the fold.
2) Reports suggest that over the last 2 years Putin completely isolated himself and spoke to very few people, including his top advisors. If the cancer story is true, and he hid away because of his reduced ability to fight Covid due to that illness, he probably used that time to plan this invasion. His 10m meeting table also adds some weight to the low autoimmune theory. In short, he has limited time in front of him.
3) From the very outset Putin threatened nukes, presumably to avoid any drawn out conventional conflict with the West. Nobody in their right mind was going to call his bluff on that, so he almost certainly believed that walking into Ukraine was going to be a pushover with little or no resistance given the West's inability to assist. It should have been a 5 day war at worst given the overwhelming odds in his favour.
4) In the press conferences Putin has televised to date with his Generals, they appear to be far less convinced about the Ukraine operation that he is. They are clearly being ruled and told what to do and say with an iron rod and they didn't appear happy about that. Its therefore unlikely that either Russia's military or Russia's population would have any appetite for attacking other countries once the Ukraine issue is resolved (one way or another).
5) As we know, overwhelming a country with military force is considerably easier than governing that country once the shooting stops. In the case of Ukraine, the country is so "westernised" that insurgencies would continue for decades to come and Putin would need tens of thousands of agents on the ground to accomplish order in a population of 15m. A shortcut for establishing direct or indirect rule would be to have Kiev governed by Belarus and its military that are just a few Kms away compared to Moscow. Perhaps that's why Belarus is playing such a major role in the conflict.
5) It's always possible that Putin has simply "gone mad" and is holding the world to ransom with his nukes in order to get his own way with the least amount of resistance possible. That strategy is clearly working for the moment. It's a short game however, and if he is going to die soon anyway why should he care about nukes? The best that can happen for him is that Ukrainian resistance crumbles and the West just roll over and pretend life goes on as normal. The worst that can happen is that he loses the conflict and the sanctions bite so deep for his population that he is publicly humiliated. It's at that moment the world should hold its breath.
In any event I don't believe Putin's ambitions stretch any further than Ukraine, and I don't think the Russian military or the Russian population have any appetite whatsoever for major conflict. Ukraine is a personal grievance for Putin that he is hell bent on winning, and he has captured the world as pawns in his game.
