If I was asked to write an essay on the topic, "Karl Marx, Genius of the Modern World," I believe I would have to argue in the negative.
Nonetheless, there are positive aspects to the man. We have to see him as a product of his times and appreciate his concern for the lower social classes of his times. As most histories of the nineteenth century will tell us, life was tough for workers.
We must ask however, did his influence lead to better conditions for workers? I have a suspicion that it did - in a funny sort of way. The final revolution in Russia (under Lenin, advocating Marxism) scared the 'shit' out of the ruling classes of Europe and North America and the threat of revolution led to a series of reforms during the twentieth century, though it may be hard to isolate Marx's influence against the influences of other economists.
For anyone interested in understanding Marx's influence, rather than just shouting abuse, you could look at this selection of the "Ten most Famous Economists of all Time." Its from an UK university site:
(Reference: https://www.thecompleteuniversityguide.co.uk/courses/economics/the-ten-most-influential-economists-of-all-time/ )
Adam Smith is listed first and Karl Marx second, and John Maynard Keynes (deservedly, I think) is third. When it comes to the twentieth century generally, I think the selection would provoke a lot controversy. For example. the list leaves out any mention of the UK economist, John A. Hobson.
But whether one agrees with the listings or not, it helps us to understand that Marx was only one voice is a world that needed change. Our world likely continues to need change, not just from the viewpoint of poverty stricken third world people, but also from from the viewpoint of first world citizens as it seems that a greater percentage of wealth continues to be accumulated by a smaller and smaller group of wealth owners
If you want to understand the western world of the Marx;s time, you could try reading, Howard Zinn's, "A People's History of the United States." or perhaps this Sage (publishers of Academic Journals) web-page:
"The American Worker: The War Between Capital and Labour." (Web-Link: http://sageamericanhistory.net/gildedage/topics/capital_labor_immigration.html )
And reverting to Marx himself, in what seems to be a review of Jonathan Sperber's (Book) Karl Marx, (Published by Norton). The UK Guardian asks, Is Karl Marx still relevant ? in a 2013 issue.