I've come across multiple people online who maintain that actually Dialectical and Historical Materialism and Scientific Socialism are not Marxism and were invented by Engels and later used by Stalin to justify the brutal totalitarian bla bla bla.
Obviously it's a specious claim, but does anyone know its source? Is there a specific tendency that claims this? Is there a book or a podcast that all these losers are consuming?
One of the primary disputes between Trotsky and Lenin (and then Stalin) was the degree to which the state can dictate the trajectory of history.
Lenin's decision to seize federal power was a break from the Marxist organizing philosophy that was skeptical of individualist agency and efficacy.
The whole theory of a vanguard party was unorthodox to classical Marxism, but necessary from the perspective of activists pursuing Marxist policy.
When the people that I've seen make this claim talk about it, they're not disputing Marxism-Leninism or the party form. They specifically (at least from what I can decipher) seem to believe that dialectical materialism and scientific socialism themselves were introduced by Engels.
Oh well... then you're just trying to read the tea leaves between publications and sort out Marx's views from that of his most avid supporter.
That sort of argument leans heavily on Marxism as a Cult of the Man rather than a working philosophy of economic analysis.
Who introduced the views should not ultimately matter. These are published ideas and theories, not prophetic revealed truths. If a published statement is flawed, it shouldn't matter who wrote it.