With what?

Russia has been wringing itself out to find enough soldiers to continue the war in Ukraine, and while they haven't been driven out just yet, I think it would be somewhere between "a massive stretch" and "flat-out untrue" to say they're winning.

And by and large, the rest of Europe is farther away, has a much worse/less clear casus belli from Russia's point of view, and, crucially, is part of NATO, and thus will not be fighting alone (and yes, I know Ukraine is getting a lot of support from Europe, but support isn't the same as boots on the ground).

If Russia launches an offensive against the EU, there's a damn good chance that offensive boomerangs right back around into its face.