And yours is appeasement.
No, in fact, my idea removes the operative rationale for the war in Ukraine before it begins and cedes no territory.
Just face it, self-proclaimed foreign policy "realist":
1)a situation in which the two largest nuclear arsenals have a bunch of hostile launch platforms near one or the other is an existential threat to life on earth from the simple possibility of error alone, not to mention the temptation of an idea like the preemptive nuclear strike against the Soviet Union attributed to Barry Goldwater.
2)conferring a NATO article 4 or 5 guarantee on a place that could be host to such a set of hostile launch platforms is, from the standpoint of the encroached upon nuclear power, as good as putting the launch platforms there because once that guarantee is in place interfering with the placement of launch platforms also results in a nuclear exchange or the abeyance of the treaties that govern NATO. Trusting adversaries to let their treaties fall into abeyance in order to save the world on short notice is silly.
3)#1 and #2 both being untenable situations for both the encroached upon nation with a vast nuclear arsenal and the existence of humanity as a whole, the threat of extending NATO membership to a country on the border of a giant nuclear power designated hostile is as good as threatening world suicide.
4)If the military alliance that is threatening world suicide refuses to negotiate terms to step back from the brink, then what is there to be done? How is it acceptable to expect a country to face that choice and make the decision that seems to march inexorably toward the end of the world assuming NATO keeps acting in the same way?
5)The prospect of NATO membership for Ukraine without guarantees related to the security of Russia is a suicide pill for the entire world and that takes precedence over Ukraine's freedom to be a belligerent idiot joining a gang of other belligerent idiots.
You can have a global system based on nuclear deterrence or you can have a global system in which smaller nations everywhere can justifiably have full diplomatic and military freedom of association. Pick one because you cannot have both.