It’s quite simple. Resource extraction, and coloring more of the map in his country’s color.

Russia’s reasons for invading Ukraine mostly boil down to the same, although their country is so fucked, they actually need to forcefully graft 40 million people onto their population against their will, just so Russia can survive another generation, Russia is a doomed country demographically, America isn’t, America is doing it just because. That’s Ultranationalism and Fascism for you. Making enemies to distract yourself from internal strife