As you can imagine, Marx wrote a bunch of stuff, ranging from the theoretical analysis of a market economy to the (alleged) historical laws showcasing the impending socialism to practical proposals in the meantime, to make things better for workers. I do not claim to be an expert on his thought.
In some places, Marx argues that socialism/communism won’t come until capitalism has been completely developed and then falls away because of its internal contradictions. This is why Mises says that to be consistent, Marxists should embrace laissez-faire.
However, as I’m sure you know, in the Communist Manifesto, Marx & Engels give a laundry list of State interventions into the economy (many of which we already have!).
I found this article saying that Marx apparently chided another socialist of his day, for arguing that raising the pay of workers would reduce employment. Marx (assuming the author is correctly paraphrasing him) argued that it was more complicated than that, and so perhaps Marx would support minimum wage laws.
I don’t think we can argue that Greece is socialist/communist. I am more sympathetic to the claim that Venezuela is, since the government there (under Chavez and Maduro) has taken so much control of the economy. If you refer to the tweet I mentioned in the other thread, I also show that Venezuela is literally the 2nd from bottom in Heritage Foundation’s latest ranking of Economic Freedom.