I know inventing reality is your whole schtick, but Marx was in fact a Materialist. Politzer’s Elementary Principles of Philosophy makes this very clear.

I’m not going to take you too seriously, you have previously denied all 3 major components of Marxism, those being Socialism, Historical and Dialectical Materialism, and Marxist critique of Capitalism via the Labor Theory of Value. Any actual analysis of Marx by your part needs to be viewed with the highest level of skepticism to begin with.