You have asked two questions. One is about the Russian internal situation, and then there's the nuclear thing.
Let me put the nuclear thing in one way. I don't believe they would be considering limited nuclear war. I think most deterrence strategists believe that there is no such thing as limited nuclear war. If you're going to threaten, you're going to threaten thermonuclear.
The best historical example I can give you of that is John Kennedy in the1962 Cuban Missile Crisis. He didn't expect to use the things, but he went to Defcon 3, which is a level of alert next to nuclear war, to make the point to the Soviets and to Khrushchev that he was serious. Basically, he got what he wanted with that threat. The internal situation in Russia, though, is that Putin continues to maintain control. He maintains a very stable situation.
He has issues. He has the ultra-nationalists. They are giving him more problems than the so-called liberal democrats—guys like Navalny, who's in prison, or Kara-Murza, who's just been sentenced to 25 years in prison. In the Russian system, these people are political outliers. The mainstream people are the technocrats who help Putin run the government. Basically, they don't have an alternative other than to keep going.
The ultra-nationalists are pushing Putin to do more, not less. Putin's problem is that he's actually fending off people who say that he should be fully mobilizing, that he should be trying to take out the government in Kyiv and that he has to go west. That's what Putin is trying to manage all the time.