What Marx would have wanted for the present day is like talking about who Lincoln would have endorsed. His theories were grounded in how the early industrial revolution conducted itself towards labor, horribly, and a working class with zero political power. Things are different today somewhat but all politicians in any society speak of class struggle and populist empowerment because nearly all of us accept the concept of class and no one really likes to think they might serfs in a plutocracy.
Marx could not see that capitalism could change and government and capitalism could exist in a limited mixed economy and that the government could provide a social safety net during bad times like FDR's mostly temporary New Deal.
That is a certainty, practically no one on the left takes Marx as the gospel, more like one of many philosophers that formed the bedrock that underlies All modern economic theory. Most leftists today favor the Democratic socialist model rather than anything that is recognizably Marxist like abolishing private property. He may be considered one of the fathers of socialist thought but he was never the last word.
But he wanted one party control over society, culture, and economy. Just like modern PC, social justice, socialist, Bernie Sanders Democrat Party.
Marx did not want that, you talking more about Stalinism, no one wants that. The things you say are just the same have somehow not resulted in Gulags, state run media or broad nationalization in any western democracy, the slippery slope theory is based on something that has never happened. What you think of as authoritarian socialism has only ever followed fascist states, dictatorships or monarchies.