Late Stage Capitalism

I'm sorry, but this just reveals that we aren't on the same page when it comes to Marxism. Your primary error is with erasing all of the advances of historical materialism and scientific socialism from Marx, and returning it to the utopianism of pre-Marx socialists such as Robert Owen. Essentially, you are treating capitalism as "private property," socialism as "public property," and communism as "big socialism." This is dogmatic, and erases that modes of production are NOT their finite parts, but instead are determined by which aspect of the economy is principal, ie dominant and rising, and which class controls the state.

When you say China is a "mix of capitalism and socialism," this horrendously misrepresents what a mode of production actually is. In China, public ownership is the principal aspect of the economy. Huge state industry forms the backbone of the economy, and governs the large firms and key industries. This is because public ownership and planning is more effective at higher levels of development.

The private property that exists in China is relegated to small and medium industries, and highly competitive ones. This is because of the key development in Marxism advancing it beyond utopianism: the form of production suits the level of development of the productive forces. Rather than taking the Utopian path, which was to "model build" and create a system outright, Marx observed that capitalism came from feudalism with the rise in industrialization, and that markets themselves were centralizing, in other words socializing production while keeping profits private!

To return, your position that "the more communist you are, the more you dogmatically collectivize, regardless of level of development" is distinctly anti-Marxist, and moreover was already tried by China! Under the Gang of Four, there became a fetishization of equality in poverty. They were dogmatic in trying to collectivize as much as possible, with little regard for the level of development. Reform & Opening Up was a return to more classical interpretations of Marx, and thus saw a stablization and slight acceleration in development. This strategy and understanding is reflected in Cheng Enfu's diagram, here:

When Marx and Engels wrote the Manifesto of the Communist Party, their basic advice to any successful revolution is to nationalize the large firms and key industries, develop the productive forces as rapidly as possible, and gradually nationalize the rest of the economy as it develops. This reflects the exact path the PRC is charting, right now. This is why it's important to read and understand theory, as if you became a leader of a new socialist country with your current understanding, you'd likely commit the same mistakes as the Gang of Four.