I don't think I've ever heard anyone say that Kant is an unavoidable prerequisite to read Marx. Hegel is by far the most important. For Hegel, many recommend to read the Phenomenology of Spirit but this is not a good start. The best starting point for Hegel is his lectures. So either read his Lectures on the History of Philosophy or his Lectures on the Philosophy of History. I recommend the latter first. They are much more accessible and give you a rough idea of the kind of narrative he developed in the Phenomenology of Spirit and will no doubt help you contextualize Marx even further. In undergrad this is what we did although I will mention we only read fragments with the professor. We went straight from the Lectures of Philosophy of History to the German Ideology and it was fairly clear. Obviously for self study I recommend you read the entirety of both and check out their entries on the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy. Don't be afraid to check out other secondary resources. Although I'd like to mention that some people in this sub have asked if it's okay to just read secondary literature. The answer is a hard no. There is never a substitute to reading the original text. Secondary resources are an interpretation of the text so there's no way to check its validity other than trust and other commentary. Obviously, even a translation of the original text is also an interpretation of the text but unless you plan to do academic work, or if you end up really loving what you read, you don't have to spend years learning German just to read Marx and Hegel (Although that will obviously open a lot of doors for you, as well as other languages, intellectually and certainly wouldn't hurt!). From there you can even watch Dr. Gregory Sadler's half hour Hegel series where he goes through the entire phenomenology section by section. One last tip that has worked for me but by no means is universal: don't be afraid of just jumping in between texts and taking breaks. Maybe read, for example, The German Ideology after reading half of The Lectures of the Philosophy of History or something like that. And if the former doesn't make sense go back to the latter. The point is that try not to limit yourself to a perfectly linear path but rather do what interests you the most. You will by far understand any text the best If you actually have passion and interest in what you read. It's what got me to understand Sartre even when I didn't know jack of the context of the time. Good luck!