No way. Why hasn't Putin ended the war already by dropping a one 10 mega ton nuke on Kiev? I'll answer - because nuclear weapons are bluff weapons that can never/will never be used in a FIRST strike.
You are not keeping up with what is going on in the nuclear policy debate at all. The situation is not at all how you envision it.
Here is a place to start https://www.usni.org/magazines/proceedings/2022/december/navy-needs-low-yield-nuclear-weapon
“because nuclear weapons are bluff weapons that can never/will never be used in a FIRST strike.”
Maybe, but places like RAF Lakenheath practiced for decades doing a nuclear first strike should Russia attack.