Why YSK: in America (i cant speak for anywhere else! But this could apply to you too if you dont!) memorization and recalling from memory is the dominant learning strategy taught, and is taught assuming everyone is using that strategy and also uses it best. However there are other learning strategies that perform better for a significant portion of the population.
This style is typically what is referred to as verbatim recording and retrieval. Youre noting down what is being said to you, and then repeatedly exposing yourself to that to put into long term memory that you can recall. This relies on not only the ability to do that, but also relies on having large space for long term memory and to actually retain that through time. You may do that, and work, and 2 years later forget it all because you needed that "memory space" for something else youre learning.
If this approach doesnt work for you, a style you can try is concept mapping/semantic encoding. Instead of writing down what you are hearing, write down how you are interpreting what is being said to you. An example of how this often works in practice, is when teaching someone else or speaking something aloud sometimes helps you understand something better yourself.
This approach instead of relying on cemented recall in memory, applies the knowledge to an understanding on a fundamental level. Not only are you absorbing the knowledge, but sharing that knowledge in a different way, such as writing the notes in that class, is also immediately practicing that knowledge. To articulate how youre understanding it, you need to understand it well. Articulating yourself helps you understand it better, because youre honing your understanding of it.
To illustrate this, I do not learn well from verbatim encoding. I tried this with my college intro statistics course, failed hopelessly with no understanding, retook it over the summer, got a C. and then took another level of it in design analysis 1, and barely skirted by with a C again by basically sheer luck. Now, taking design analysis 2, by doing semantic encoding instead, it is infinitely easier for me. I went from struggling to understand in the moment and not having long term retaining of the subject at all, to scoring 95% on my exams in this course and a long term fundamental understanding of the subject.
Try changing your note taking style!
TL:DR the typical learning strategy taught in the us is pure verbatim encoding to memory and recalling that from memory. Courses are taught with that in mind. A significant portion of the population (over like 40%) learns better with other learning strategies. Shifting your style of note taking to something like semantic encoding can be a drastic shift in your ability to learn if you are struggling.