I actually think the Ukraine War, fight to a draw or stalemate is now the best case scenario. Or Putin is assassinated by external or internal means and cooler heads prevail.
I think it’s a huge mistake to keep calling Putins nuke threats, A bluff. It forces his hand when he is pushed too far.
When Ukraine gets the jets into action. And they take more ground. Putin will either start testing Nukes in northern Russia, as a show of force.
Then would most likely use the short-range Iskander-M missile. 1–50 kilotons, a blast radius of about a mile wider than the bomb the U.S. military dropped on Hiroshima. Hopefully China would then separate themselves from Putin.
I don’t think NATO would escalate and go full nuclear war on Russia. They would then negotiate terms.
IMHO this ends one way or another with Russia gaining some Ukrainian soil. There is no 100% winning scenario. Putin is not going to lose face.
The other option is full out WW III troops in Russia, China and N. Korea