It's not just energy prices.

Russia and Germany used to have the trade relationship that Russia has with China now. Russia would sell Germany a lot of cheap fuel and raw materials, and Germany would sell back to Russia a lot of finished goods (like cars) cheaper than normal. Russia was basically financing Germany's industrialization, while Germany was financing Russia's standard of living rise.

Just for perspective on how sanctions on Russia have actually hurt Europe: Germany has chronically been the #1 vehicles exporter worldwide by value. China used to be hovering between #5 and #10. Right now, Germany's lead has dropped almost by half (from 400 billion to 250 billion dollars). It's still #1, but China is following at #2 at 60% of German export value (150 billion dollars, up from 50 billion a few years prior). China's primary vehicle import partner is now Russia. Germany's primary vehicle import partner before sanctions used to be Russia.

And by the way, this is going to be catastrophic for the whole of the Eurozone. The Euro relies on Germany's strong export economy to stay strong, since every other economy in the Eurozone is an import economy, running at deficit budgets. Germany actually likes this, because that way the Euro doesn't become overvalued, and their exports don't become overpriced, and they don't otherwise have to keep printing money and dealing with inflation fluctuations all the time.

If the only economy that is supposed to keep the Euro viable is now tanking, then the EU is about to get destroyed.

Of course, that's what the US wants. A weakened Europe that depends 100% on the US economy, instead of independently getting stronger while getting Russia stronger as well. And most importantly, full energy reliance on the US, means the US can have much better control of European politics.