Read theory bruh ffs. Start with Deng's essays on opening of China's markets.

And once you've read theory, you'll find that China is in social movement. The proletarian revolution created a proletarian state. That state dominates the private market to ensure capitalist interests are subordinated to the interests of the workers' state.

USSR had the NEP for the same reason. You can't press a button and become socialist. Not how it works.

China has to balance building socialism, governing 1.4bn people, improving their material conditions, be the most rational actor in international politics, AND CONSTANTLY DEFEND AGAINST IMPERIALIST RHETORIC AND AGGRESSION.