LOL! You don't know history. Hitler invaded Russia in order to get control of Russia's oil fields. He too thought he could beat Russia by murdering thousands/millions of their people. A new 2020 statistic claims that between 15.9 and 17.4 million Russians died at the hands of the Nazis. What Hitler didn't realize that the Russians had that number, and millions more that ended up kicking his ass out of Russia, all the way back to Berlin. Hitler failed to realize just how vast Russia was, and how many people were still left in those regions to fight against him. He ran with his tail between his legs, and helped make Germany dependent on Russian energy sources for the next 70+ years.
It's not the same Russia now, and yes I do know history, and I was overseas 3 years in USAFE, in a work center that studied the Russians. The Russians have land and no people to replace the loss, and a very low birth rate.
The other factor is the rank and file Russian Conscript wants no part of fighting Ukraine.
This all with a loss of 500,000 Russian Troops up to now.