The historic core of Ukraine is just above the Dnepr River, no way is Russia going there. Odessa and Kharkiv are doubtful. Russian withdrawal around Kharkiv indicates they are not going to try to take that region.
If Russia isn't going to try to take Kharkiv, odds are they won't try for Odessa either, but Odessa might be a higher priority, in order to take the entire Black Sea coast. The Odessa region might then be a bargaining chip in future negotiations, that is, the return of Odessa to Ukraine might be traded for Ukraine's agreement to cede Luhansk, Donetsk, "Tuarida" and Crimea to Russia.
Russia maximum goal: All of yellow shaded area, plus Odessa, complete control of the Black Sea coast.
Russian minimum goal: All of yellow shaded area, complete control of Donesk, Luhansk, "Tuarida" and Crimea. Complete control of the mouth of the Dnepr River, possibly some of the north bank.
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