Which areas do you think Russia going to take back first? From Kyiv to Lyman, and from Lyman to Kherson, there are so many to choose from now. If Russia is going take back territory from Ukraine, it would be nice if the Russian army would move west instead of further east.
Russia will insist on having all of the ethnically Russian areas. The thinking is that the Kiev regime via its barbarous conduct has forfeited any right they might have ever had to govern Russians.