This assumes Russia is reasonable and they are just waiting to cut a reasonable deal, what have you seen to think that is even remotely the truth. That action would be throwing Ukraine to the wolves so I can't see how that would work. If Russia thinks they have the upper hand they will just keep pushing for more. And even if they take some sort of deal greatly advantageous for themselves how does that ensure Russia will believe aggression will not work out well? Your plan proves it does work out well and the Russians will note that and other potential aggressors will note that and allies will understand the USA is soft and not dependable. Doesn't sound good to me, sounds like a disaster.