I don’t really think you’ve captured communism: Cuba isn’t.
Communism has never yet been achieved, as any communist government will tell you. Socialism is a transitionary step toward communism. You can’t go to bed in a capitalist state and magically wake up to a classless, stateless society.
China has been moving away from communism for decades.
If you think that then you have not been paying attention to what’s been happening in China for the last decade.
Russia rejected the Communists for the Bolsheviks
The Bolsheviks were the communists! Come on. Maybe pick up Wikipedia or an even better wiki on the topic: https://en.prolewiki.org/wiki/Communist_Party_of_the_Soviet_Union
Thanks, BASIC, for teaching me so much I had to later unlearn in order to not be a garbage programmer.