Ask yourself (or research) what would it take for a country to remain socialist and still have a stock market.
(That's not tongue-in-cheek. It is the counter-side to why a country like Norway is not socialist despite having one of the better welfare systems outside of dictatorships of the proleteriat.)
Reading resources (to begin with):
A: - Why the World Needs China by Kyle Ferrana (easier to read)
B: - Losurdo (denser):
- https://redsails.org/losurdo-on-china/
- An educational trip to China, Reflections of a Philosopher
- by Roland Boer - Domenico Losurdo in China: An Insight into the State of Marxist Education and the CPC
TLDR: If dialectical materialism is a thing (it is), we have to consider in the transition from capitalism to communism via socialism what mechanisms of capital will be in the socialist state.
If you could only read one thing then I would recommend Ferrana's book. If you wanted a wider-scope theory-dense analysis than the above list then I would recommend Losurdo's work on Western Marxism.
Hope that helps.