I was playing around with ideas of civil war in Europe myself for roughly 5 to 6 years now. Since it feels like the only plausible conclusion to the mess the current elite created.
But now I'm also seeing trends that the nationalistic hardline parties are gaining public momentum in EU, not just as a response to migrant policies, but also as a response to NATO-aligned proxies attempting to jeopardize relations with Russia in trade and security.
Just looking at overall developments across EU today, the union is relentlessly stockpiling huge problems with no solutions in sight. Poland's and Hungary's rebellion against EU's elite, Turkey's successful attempts to pressure and humiliate EU, the disastrous failure of the Ukraine project, the likely upcoming war between Moldova and Russia (with semi-Romanian involvement), Baltics' utmost success at destroying their trade relations with their neighbors, and now the fairly questionable status of EU citizenship and Schengen zone as the Pandemic pretty much buried those into the ground, at least until the quarantine is lifted... it appears to me that if the EU is to survive by the end of the 21st century, it will have to undergo a very substantial transformation. And there will be a naturally strong push towards that transformation regardless of what anyone wants. This transformation will begin with the victory of nationalist/opposition parties in key west-EU states. And this slightly changes my vision of the future already. As originally, when I started envisioning civil war, I didn't consider it to be possible for the opposition to assume positions of power. How it will progress from there is hard to say, but if my forecast is anywhere near accurate, then before we'll be seeing any civil wars (if any at all) we'll first see a new refreshed elite engaging in Nazi-inspired treatment of incompatible cultures.
Alternatively, we can consider a different transformation scenario, in which the current EU establishment doubles-down on its long-term goal of the EU integration project, which foresees transforming EU into a United States of Europe federal-style country. And once it has all the mandates and tools of influence in place, it can crack down on any internal or external problem in sight. But at this point I see this development pretty implausible, as the grip over east/central European member states is loosening as things stand today at least.