Not entirely sure he meant this in the way we’re talking about here. He meant forced and imposed labor. I doubt he had the imagination to foresee a world where machines would do everything now done by people.
Or I could be wrong. If he envisioned a world in which no work would be required, I’d be interested in a cite.
In any case, if such a world was considered utopian by Marx, that does not mean of itself that it would be bad. Marxism, like Nazism, had many goals that just about anybody would consider desirable.
They had that world in the animated film WALL-E. All the people were fat and suffered atrophy and were consumed by mind numbing electronic pacifiers.