I think you’re argument is semantic, then. After all, what is called “Darwinism” today bears little resemblance to actual Darwin-style Darwinism. Same way with Marxism - the philosophy has evolved beyond its Hegelian roots as it has been expounded by later “thinkers.”
Marxism should be seen in context as a 19th century Materialist response to Hegel.
Spirited: While it is a materialized version of Hegel’s dialect, we need to dig deeper and begin with the fact that Hegel was a pantheist and his dialectic was a magic-formula based on the idea of divinized and/or immanitized history. In other words, history is a ‘divinized entity’ that predetermines specific events and outcomes.
Pantheism is paganism, or more specifically, it’s monism, the ancient idea that all things are ‘one’ with and/or merely extensions of divinized nature. In this system, man loses his individuality; he disappears into and becomes ‘one with’ Nature.
Monism is like a coin, it has two sides. One side is pantheism and the other side is materialism. Hence Marx’s materialism is paganism disguised as science. By extension, dialectical materialism is both immanitized matter (divinized matter) and Hegel’s pantheist dialectic materialized.