Much as I love a good dunk on the tankies, I find Marxism a bit lackluster in this day and age.
Marx was an important thinker for his time, and made important insights on the nature of capitalist economies, but he also lived over 100 years ago. Practically the entire field of economics developed after this point, not to mention a lot of relevant history and struggle related to his ideas.
So go ahead, read Marx, read Lenin, read whoever. But place them in the proper historical context. We’ve learned much about the world since these people lived, and the world has changed as well. They weren’t prophets whose sacred words we must follow, just a few voices among many. Take what is true and useful and discard what has been disproven.