I think Russia has three times the population of Ukraine (44M is nothing to sneeze at), 5% of the motivation of Ukraine and probably 5% the manufacturing power of the NATO bloc as well as 20% the technical capability, 20% of the logistical and intelligence ability so it's not quite as powerful as you make it out to be. Also shelling has dropped considerably to a third of what you mention 10,000 at most per day. Remember most of Russia is a vast barren wasteland and the supply of willing, motivated young men from the East is dwindling rapidly, along with Putin's personal odds of surviving another year. On top of that the Ruble has collapsed again and this time its down for the count. Pure folly.