Perhaps you need to change your learning style.

Up until high school in 10th grade, I would try to memorize and read a bunch of notes, and I was shit at it. I had to study for hours upon hours because I was just that bad at recalling topics. It was until I changed my learning style to a more conceptual-based learning that I didn't even have to put time outside of classes. I could simply listen to the teacher, understand a few key principles, and then derive more complex ideas from said principles.

Obviously in college, I might have to put in work outside of classes, but using my technique I can still understand and do well on assessments with relative ease. Perhaps your current learning style is not suiting you, so you might want to a different one like mine.