So, the challenge is to make an East bloc that actually has people liking Communism. Like there is a high standard of living, a quality arts sector with great music, architecture, cinema, animation, fashion etc, that even Westerners would admit is great. Like one of the common problems I hear is that people from the East bloc craved American entertainment as well as variety in what they had such as cars and the things inside supermarkets.
Off the top of my head, I can solve the car problem, by the East having an extensive and efficient public transportation system. I don't have a lot of time , so I leave the rest to you. Also a Democratic East bloc , so that the US can't spin the conflict off as democracy vs Communism, and instead it's clear to everyone that it's capitalism vs Communism. Plus less restricted movement, but communists who travel still prefer communism and return.
To be clear, make communism good enough that people in the East bloc aren't craving what the capitalists have. Also make the USSR as technologically advanced or even more than the west, with space travel, computers, medical science/genetics, etc. Also give the USSR more allies, like more communists in US's "backyard" Latin America and just make the cold war less one sided since most of the Western hemisphere basically had no choice but the USSR.