That's what foreigners think the Swiss army trains for. In reality we only maintain critical know-how so that we can ramp up a real army relatively fast (a few years) if the need arises.Given that Ukraine would be fighting a defensive war on it's home turf, and Russia wouldn't really be able to throw it's entire military into the problem, the imbalance doesn't seem all that bad. Isn't this the exact kind of asymmetric stuff that you guys (the Swiss) train for?
As for Ukraine, if it was only the number imbalance it'd be something but their hardware is in terrible shape. For example, their best main battle tank is a souped up T64, they probably wouldn't even see Russian T-90s before being destroyed.
It's a war Ukraine cannot win but yes, if the Ukrainian army decides to put up a real fight it might not be a war Russia can win without getting punched in the face a few time.
Ever. And they got nukes.