They way I have understood this (a very simplified way probably) is that state capitalism is when the means of production are mostly owned or controlled by the state, but the market/economy is operated in a capitalist way (competition, growth, for profit etc.). The country can still be socialist and for example in China this shows up with the heavy regulation of things like cost of housing where the capitalist way can never outdo the peoples right to housing.

In a way capitalism with socialistic features (keynesian) and this aka socialism with capitalist features are two ends of an opposite spectrum.

In a world that is mostly capitalist, doing state capitalism also sounds like the only workable option for a socialist country.