Put your notes in OneNote, and divide them into 4 or 5 high-level categories (1000,2000,3000, etc). Then split those thousand groups into hundreds groups, tens groups, etc. Something magic happens to your brain when you start using numbers to group things. Not sure what it is, but overtime you’ll find yourself using the number and not even saying the title anymore. Also having dedicated buckets for things relieves a tremendous amount of anxiety. It takes a while to build and it’s incredibly an unintuitive thing to build out, but it really helps. Check out schemes and the top level pages on wikipedia, or maybe various classification systems.
So for example btw:
1000 - Liberal Arts
1100 - Philosophy
1200 - Law
2000 - Natural Science
2100 - Chemistry
3000 - Applied Science
3100 - Agriculture
3200 - Engineering
3210 - Mechanical Engineering