Oh yeah, I'm sure Ukraine will really stand up to Russia. It's not like there was a Russian invasion where they folded like a Cheap suit.
The Russian campaign to take Ukraine would last a week if Ukraine receives no help from the outside. maximum.
Poland would be a much stiffer fight, but without France, USA, and the UK involved they couldn't hold out forever. And Germany is not even a consideration, they are such Betas, they didn't want combat roles in Afghanistan, their military is underfunded, most of their air force isn't even combat ready.
Of all the NATO countries, only UK, France, Poland, and Norway have competent militaries, and they're not going to be able to take on Russia alone, assuming there was a full on declared general war.