But its difficult to say if he had everything figured out because his "dictatorship of the proletariat" doesn't seem to ever actualize in a lasting fashion. It usually ends up as an authoritarian state arguably because the system is vulnerable to the first group that decides to break faith with the covenant

This is a fundamental misunderstanding of the DotP and Communist history in general. The PRC has a DotP, the USSR did, Vietnam, Cuba, Laos, etc. All have a DotP. Read Why do Marxists fail to bring about the "Worker's Paradise?" You have an odd, idealistic idea of Marxism that even Marx would deny.

A lot of Communist hopefuls tend to either take the examples of this happening as "not true Communism" or try to minimize the bad aspects of regimes that adopted the principles... It does seem once power is too laterally spread it becomes weak to any hierarchy that as long as they can talk a good game and use Marxist language.

This is just a bunch of gestures. The reality is that AES states are truly guided by Marxism, and are true attempts at Communism, but haven't made it to the Communist stage of development.

In either case a lot of us would not call those outcomes "proven correct". I would say he had some very lasting ideas which are useful tools... But the fact that none of the places where attempted enactment have particularly lived up to his hype means that like a lot of philosophy of his time that the answers are a lot more complex and nuanced than he could have forseen.

They have absolutely lived up to the hype, coming with drastic reductions in poverty, wealth inequality, increases in life expectancy, housing rates, ending famines, free healthcare and education, democratization, and more. Please, read Blackshirts and Reds.