This is a country that needs to be broken up.
Give a piece to Hungary, some to Poland, a chunk to Slovakia, some to Belarus, if Moldova can make peace with TransDniester, let them have the coast up to an including Odessa, and let Russia have the rest.
I think all those countries will be happy, and the people living in the former Ukraine will also be happy too. Give them 6 months to switch locations if they want, and then freeze the new borders.