However the capital that flowed into it certainly was, if China had not opened itself up to foreign capital it would not have industrialized anywhere near as fast as it did.

They found a strategy to avoid being cold-wared by the global north, that's not something a global north country does by definition

Until they saturate their markets and start to look outside their borders for new markets.

It's not just capitalism in a vacuum, it's a set of specific things that systematically happened in capitalist global north nations because they were dictatorships of the bourgeoisie. The phenomenon includes monopolies, banks and financial markets, three things that China is actively keeping under control.