I think a realistic reimagining wouldn't involve Stalin actually continuing to march west from Berlin but instead involve the Soviet Union supporting communist revolutionaries west of the iron curtain rather than abandoning them a la Greece. This would've resulted in another hot war while the ink was still drying from the last peace treaty, but hopefully this time the Germans actually take up the side of the Soviets rather than wavering like they did post-WWI. I don't know if it would've changed the outcome, if the USSR would've won the fight against global capitalism, but by sealing themselves off they ended up losing anyway. They needed the support of industrial workers outside of the Eastern bloc and they never got it because they chose to protect what they had gained rather than risk it all. Pursuing this route though ended the ascension of communism in the 20th century, leaving behind fledgling socialist projects without the industrial base to truly compete with the US and global capital. Only China is now positioning itself to take on that challenge but it took decades of building infrastructure and a Faustian bargain of market liberalization to get there