Do you have dyslexia, or some other issue? If so, there are methods to deal with that.
But if you just have trouble understanding, there are different “Learning modalities” as they’re called in education. Some people learn better listening to a lecture, others learn better by reading, and so forth. Obviously, making slides (taking notes-kinesthetics) is the modality that works for you. (It might not even be the slides that help you, but the act of CREATING the slides).
With that said, reading a dry, boring, complicated, poorly written article can be a nightmare. Chances are the article/text has been written by someone who, although knowledgeable, is a terrible communicator.
So, I don’t have an answer for you, but I empathize with you. Rather than going to the trouble of making slides, maybe just try taking notes. Just the physical act of writing might help your understanding.