1)
The 1989 accords that governed the breakup of the Soviet Union, stipulated under agreement that any if the new countries that failed would revert back to Russia.
Crimea us ethnically Russians and it operated its own government separate from Ukraind but made up if Ukrainians. When that government got corrupt and the Crinean Russians revolted, the Crimean government vacated. Merely walked out and left the doors open. It’s to revert to Russia and that’s what the Russians in it want. Russia incorporated it in 2014. Ukraine wants to claim it instead. So I can understand Russia’s insistence on that area. But Donbas - ok it had mining. Once Putin had the bio weapons facilities (proxy for the US,) then he wouldn’t need Donbas surely?
I mean it’s a proxy war anyway, deep state vs Russia so do these regional objectives matter anyway