I used to take many Cornell Notes (on paper) back in the days and find that I even still use some of these.
But I transcribe the ones I need (and only those) into Obsidian and actually scan & crop the graphs (use them as PNG or SVG in Obsidian).
As required with Cornell anyway, one should build their own ideas/questions and summary from the notes taken in a lecture, and I find actually transcribing some of the old stuff into Obsidian helpful. (Spaced Repetition → Memorizing and forming/linking ideas/questions/conclusions in Obsidian).
Since I’m a bit of a techie, and use LaTeX for creating books and papers, I’d use formulae as an excuse to learn LaTeX math (same used in Obsidian) and thus get your formulae typeset beautifully (and easily reusable if you have to write a paper).
So I would (and actually do):
- transcribe all needed text into Obsidian,
- scan (or download from notetaking device) and crop graphs and drawings,
- typeset formulae (within Obsidian),
- use Obsidian to build a knowledge-base (but keep focused on what kind of output, i.e. an academic paper, is your goal).
Over the past 40 years or so, I found that
- only paper really survives, and
- organized raw text files are the next best thing (no dependence on ever-changing/abandoned proprietary formats). And searchable! I had to convert hundreds of WordStar files made back in the CP/M 2.2 days, but those created with ed even work in 2021.
- backup, backup, backup is crucial. I’ve lost so many files over the decades … but backing up some folders of text files is easy.
- keeping stuff together pays. Don’t follow the OS’s way to separate everything based on type, but keep everything needed for one project/goal together (like text, images, graphs, drawings, spreadsheet files, …)! It will be much easier to find and backup.