This is not at all what Marx believed. I understand where the misconception comes from though.

Marx was quite particular amongst socialism because he did not believe humans were equal in ability.

Indeed, he argued with other socialists and believed that different people had superior and inferior abilities, and even that the more productive people logically deserved a higher wage, and so did the people with greater need.

This is why unlike other socialists of the era, Marx did not advocate for equal wages - he thought that people that were more productive should have a greater income (as well as people who needed it, ie, people with families, handicapped, etc...)

He also did not believe that conditions would not improve - he was a radical proponent of economic growth, and thought that things would improve for a significant amount of time until a plateau was hit, at which point a transition to communism would be the only alternative to decay.

Instead, Marx's argument was not that capitalism created inequality - he thought that inequality was inherent to the human condition - but that capitalism fundamentally engendered inequality on the basis not of personal ability, but on the basis of artificial social relations that rewarded the ownership of capital far more than the inherent inequality of humans ability and human need.

He also would vehemently disagree that voluntary trade worsened the situation of the working class - he wrote extensively about how capitalism was an immense improvement over feudalism, and how it would and was improving the situation of the working class materially. The issue he had is that the thought that this material improvement would eventually stop contributing to well-being, and that eventually the social harm caused by the capitalist social relations would lead to a plateau then decay of overall wellbeing.

If you look at his immediate suggestion in how to improve them, you would find them much more inline with modern welfare states than anything else, and indeed that was why Lenin basically instated a welfare state when he took power.

Here are the actual policies that Marx wanted to see implemented:

1. Abolition of property in land and application of all rents of land to public purposes.

2. A heavy progressive or graduated income tax.

3. Abolition of all rights of inheritance.

4. Confiscation of the property of all emigrants and rebels.

5. Centralisation of credit in the hands of the state, by means of a national bank with State capital and an exclusive monopoly.

6. Centralisation of the means of communication and transport in the hands of the State.

7. Extension of factories and instruments of production owned by the State; the bringing into cultivation of waste-lands, and the improvement of the soil generally in accordance with a common plan.

8. Equal liability of all to work. Establishment of industrial armies, especially for agriculture.

9. Combination of agriculture with manufacturing industries; gradual abolition of all the distinction between town and country by a more equable distribution of the populace over the country.

10. Free education for all children in public schools. Abolition of children’s factory labour in its present form. Combination of education with industrial production, &c, &c.

These are certainly quite radical. But all of these are suggestions that are either already implemented today in capitalist countries, or that liberal capitalists have advocated for. Except for 1., 3. and 2., he was actually correct about how to improve the conditions of the working class - the abolition of private property of capital was his eventual goal, yes, but he was incredibly precient about the policies that would be used to improve capitalist society.