Anywhere where the working class rose up against the bourgeoisie/upper class because of their "mistreatment" (sense of victimhood instilled in them by Marxism), became dramatically worse in its civil liberties, and in its economic trajectory, in every respect.
And in most places there was no such uprising, and incidentally, those places fared far better.
So no, Marx was resoundingly proven wrong.
Even during his own lifetime, some of his pseudoeconomic ideas/doomsaying was proven wrong.
He claimed, like many demagogues and economic laymen, that automation would reduce the demand for labor, and with it, wages:
https://www.marxists.org/archive/marx/works/1847/wage-labour...
>>But even if we assume that all who are directly forced out of employment by machinery, as well as all of the rising generation who were waiting for a chance of employment in the same branch of industry, do actually find some new employment – are we to believe that this new employment will pay as high wages as did the one they have lost? If it did, it would be in contradiction to the laws of political economy. We have seen how modern industry always tends to the substitution of the simpler and more subordinate employments for the higher and more complex ones. How, then, could a mass of workers thrown out of one branch of industry by machinery find refuge in another branch, unless they were to be paid more poorly? and
>>To sum up: the more productive capital grows, the more it extends the division of labour and the application of machinery; the more the division of labour and the application of machinery extend, the more does competition extend among the workers, the more do their wages shrink together.
This was proven wrong in his own lifetime as factory worker wages rapidly grew in industrializing Britain.