I'm just an internet rando, but I might offer to lift the sanctions if Russia withdrew its troops from everywhere but Crimea. If the Russians take and hold Mariupol, though, then no deal of any kind.

Re: neutrality, what do you think the margin would be in a popular referendum on joining NATO "a few months after Russian troops withdraw?" 90/10 yes/no? With some people only voting "no" because "we don't need those pansies, we just need their missiles!"

On that point, Ukraine can be "neutral" (as in not a NATO member) and still be armed to the teeth with NATO weapons. I'd love to see their air force, for example, operating something like 3-5 squadrons of F-16Vs (the model we sold to Taiwan) and one squadron of UK-spec F-35Bs that can fire the MBDA Meteor long-range air-to-air missile...