Ukraine offered an alternative approach. They are willing to compromise on territory - i.e. stop fighting over it, not give up the claim to it. What they want, and they've said it again and again, is a security guarantee for the future to prevent Russia invading again. Either membership of NATO or a specific treaty. This is their one goal beyond coming under the control of Russia during this specific war, not having to worry about being invaded again. If they don't get it then they're likely to start developing a nuclear deterrent (they've already indicated this and they probably have the capability).