I guess my reply wasn't worded so well. I don't really mean in-class notes. In class, I do the same thing you do - I write everything down on paper. In the past I have tried to type everything and ran into the same problem you stated. What I currently do is move most of my written notes into class independent documents on Overleaf. It then become easy to create study guides for exams since all of my notes can be printed and shared from a single document. Sorry for the confusion!
Are you able to save your notes out of Overleaf in the free version? It looks like a nice service but I don't want to pay to have offline access to notes especially since I like to have a nice git repo with all my old notes backed up.