My guess would be something like this: Russia pulls back, leaves Zelensky remains in power, eastern regions given full autonomy and Ukraine promises to remain a neutral country in perpetuity like Austria.
Something like this is possible. I certainly think the eastern regions will have to be given to Russia in any hope of a peace treaty. I am not sure Ukraine will go for the neutrality though. How can they, after such aggression has been shown to them? This has just displayed how crucial being in the EU and NATO is for them.