No Marx and Engels say that a dictatorship of the proletariat to hold down the proletariats adversaries whilst creating the material and spiritual conditions for the withering away of the state once a new generation has been raised in these new conditions without exploitation of man by man

We know from the 20th century experience that this could take hundreds of years given capitalist encirclement, capitalism resilience and the fact the colonial countries are the ones that benefit the most

Between capitalist and communist society there lies the period of the revolutionary transformation of the one into the other. Corresponding to this is also a political transition period in which the state can be nothing but the revolutionary dictatorship of the proletariat.

Marx, Critique Of the Gotha Programme

Now, since the state is merely a transitional institution of which use is made in the struggle, in the revolution, to keep down one’s enemies by force, it is utter nonsense to speak of a free people’s state; so long as the proletariat still makes use of the state, it makes use of it, not for the purpose of freedom, but of keeping down its enemies and, as soon as there can be any question of freedom, the state as such ceases to exist.

engels

In reality, however, the state is nothing but a machine for the oppression of one class by another, and indeed in the democratic republic no less than in the monarchy; and at best an evil inherited by the proletariat after its victorious struggle for class supremacy, whose worst sides the proletariat, just like the Commune, cannot avoid having to lop off at the earliest possible moment, until such time as a new generation, reared in new and free social conditions, will be able to throw the entire lumber of the state on the scrap-heap.

Of late, the Social-Democratic philistine has once more been filled with wholesome terror at the words: Dictatorship of the Proletariat. Well and good, gentlemen, do you want to know what this dictatorship looks like? Look at the Paris Commune. That was the Dictatorship of the Proletariat.

Engels, Civil war in france