Not much chance the Russians are going to give up “the bread basket of Europe”.
Right-bank (of the Dnieper) Ukraine is gone and not to come back.
The Crimea, Odessa, Donbass might improvise on their own. Putin is not going to risk starting world War II over it. The best he can do is to foment unrest there, get to a referendum, then muscle his way into becoming a guarantor of Eastern Ukraine sovereignty. That is very unlikely to pan out for him, but it may.
Given the mentalities involved, there may be a Cold War II, with RF isolated politically from the West and seeking an economic alliance with China.
But this far Putin’s game was to be a fair cultural alternative to the West, not the USSR redux. He’ll back out.