The Big Nuke war that kills all civilization will never happen. Just like Hitler didn’t blanket London with poison gas in 1940. If used they will be deployed in theater in a limited way. No city killers used. Putin has other weapons he can use and deploy them against the US and UK—What are they? 1) Terrorism via Iran and Hezbollah—blow up a few power stations, refineries, or football stadiums. 2) wreck our food production—Bird flu to force us to kill our chickens, Hoof and Mouth disease to kill cattle and milk cows. 3) Spread data real and fake on Biden, Hunter, Harris, Trump, a few leaks to the right people and Americans will be at each other’s throats. 4) targeted assassinations—make sure you have a fall guy—like Iran or North Korea. 5) how about a wee bit of help with Iran’s atomic bomb project? Or with rockets to carry them? Same with other lands. 6) how about a military base in Cuba for the Russian Navy or Air force? A few old bears ready to take off might cause a few worries. How about a warship with nukes harbored in Havana? The Peter the Great Cruiser could anchor there?
Most likely since Hitler was gassed in the field in WWI served as the reason he chose never to use poison gas during WWII. You would have thought he would especially in Russia.
Sure, people forget that the President of Russia wants to win things, he will do like you said, like all world leaders do, and search for ways that he hopes will work, whether long-term or short-term, to accomplish his goals.
He won’t just give up and say, let’s all die in a nuclear wipeout of the planet.