Neither the US nor Russia would be dumb enough to strike first, so nuclear war is off the table and all of the "concerns" about it are either phony or uninformed.
The US and NATO could easily defeat Russia in a war, so I think that Joe Biden should take that step as soon as Russia invades Ukraine. Basically, we could defeat Russia in a war by utilizing the first strike plan President John F. Kennedy’s defense department team developed in 1961.
How could the US and NATO easily defeat Russia near its own borders?
Russia has 350K ground/airborne troops + 200K NG troops + can probably raise 500K -1M reserves among recent service classes with ease. They can overrun the Baltics in 48 hrs, Ukraine in probably 2 weeks, and already basically control Belarus. That's before we could do much of anything.
After that it would be effectively a defensive war for them, they can move up their mobile high quality S400'/Pantsir SAM systems into the three mentioned regions. Their airforce has about 800-1000 fighter jets. No question US/NATO aircraft and AtA missiles are much better but we would have to fight their air force over ground they control while avoiding massed SAM's at the same time. That would be a serious equalizer.
Not saying we couldn't eventual take air superiority but it would take a long time and be extremely hard fought. That's not even mentioning the fact they have tons of tactical ballistic and cruise missiles that can be directed at knocking out runways all over Europe. Without air superiority over the battle field there is no way we are making much headway and I doubt we would get it quickly in most war scenarios.