Privately, I believe most Europeans couldn't care less if Russia incorporated Ukraine. Russia is little but an oil mafia. Pay up and they leave you alone. To me, this is ALL about oil and gas. No one wants the U.S. involved, that's the hard truth but they're afraid to say it because the U.S. still has a powerful military, many bases, and control of SWIFT. So though I agree with all you wrote, to me it's beside the point. Russia may do what you suggest, but it will only be the U.S. that goes nuts. Europe will privately shrug.
I also believe Russia is playing a long game with China. It's sending a message to the West, you want us on your side or China's? The U.S. can sell more LNG to Europe or get Russian assistance with China. It can't have both.
Unfortunately, there are many f'ups on the horizon before the U.S. gets realistic.