You seem convinced that pushing Putin into a corner is without risk. Why? What condition prevails just now that would convince you the little bastard WOULDN'T use a low-yield weapon or two to grab a strategic target inside Ukraine?
Better yet, what actions do you think would be appropriate if he DID drop say, a 1-5KT device as an airburst over Kyiv or Kharkiv or some other Ukrainian city? I base my caution on the fact that he decided to change Russia's nuclear weapons use policy back around 2000. He bowed to the reality that Russia alone could not afford to try to match the combined military power of the NATO alliance so he began building low yield weapons and creating a new policy for their use in CONVENTIONAL conflicts.
If he is seen to be losing this war and worse, to be backing down, it isn't just his political career that will be in peril.