I'm not thinking Russia would invade anyone. As you are all saying it'd be kinda stupid.
If I were to put on my Borscht and Vodka hat, I would start looking at ways to disrupt the logistics of weapons coming into Ukraine. Either the ships bringing it in from America, or ways that NATO is moving materiel east in Europe, or both. Russia's allies (Iran mostly but also China) are good at getting small cells of people into countries and arming them and Europe's borders aren't significantly better than ours. "Terror" attacks that happen to *expletive deleted*ck up Trail hubs would cripple logistics in Europe. As would "organic" Anti-War demonstrators doing things like the stop oil folks but on actual logistical targets, not random roads. As far as stuff coming from America, ships are as vulnerable as they always have been, and Russia's subs are still out there, and TU-95's, TU-26's, and TU-160's all mount hypersonic anti-ship missiles. It's pretty easy to track which ships load up at MOTSU and when they leave. Sure we could go back to convoys and guarding them with navel assets, but we have limited Naval capacity.
Limited strikes to interrupt the logistics of NATO supplying their proxy, and if NATO wants to invade, fall back into Russia over the winter ala 1941. That does risk the US navy getting pissed off and ending the Red Navy, but it would also put Russia in a better position with their allies and the non-NATO portions of world opinion. "We aren't invading NATO, we're just stopping their weapons shipments to the NAZI's in Ukraine. If they stopped supporting the NAZI's none of this would happen."
That's the kind of play I'd make if I were Russia, and needed to react to the West's escalation.