Question regarding Marxist materialism- if class is the primary broad contradiction under capitalism what are the primary contradictions once class sociey is abolished?

It is my understanding that class conflict is seen as the primary contradiction at least in this epoch of history. My question is, what are the new contradictions that formed under socialism thus far and what would be the theorized contradictions under communism? What was the primary contradiction during primitive communism? Or perhaps my questions show a fundamental misunderstanding, which if so I would like corrected. Thank you!