It is not a civil war- it’s a war on hired mercenaries trying to run the oligarchs. Prighozin is just one of the oligarchs, and in a very precarious position for sure. But not a civil war.
What is to be seen is if this triggers other things.
Igor Strelkov (Girkin), prominent FSB, psycho and former defense minister of the Donbass is calling it the “beginning of the Russian civil war.” He’s been right in all his predictions since the start of the war.