It’s not a very interesting question. I’m also not a Kropotkin-ist or a Paul Mattick-ist.
I think the term Marxism suggests several things:
i) adherence to a person rather than a set of ideas. I’m never keen on that. People are fallible. I’m into good ideas, not heroes.
ii) Marxism as term has been coloured by the split in the first international into authoritarians and libertarians, and has come to signify statists and authoritarian. Unfairly, but still.
iii) I’m not claiming to have read all of Marx’s output, but he did evolve his thought over time. I find several of volumes of his work useful, but I actually don’t know all of it.