You, I and others have been expecting this for some time. Russia's wide venerable borders were one of my main reasons for believing Russia wouldn't start a war with Ukraine.
People forget that many in the oil business are a nasty lot (the history of it). Even Wagner, in Iraq, tried to take control of oil assets a few years ago. That's what will amuse me. In trying to get Ukrainian assets using criminals, Russia will end up with those criminals turned against itself.
If gangs show they can take out Russian infrastructure who has the power, the gangs or Putin? Are Russian policemen going to go out looking for trouble? NOPE.
It might not be "civil war" that brings down Russia, but tried and true gang warfare.