I still take lots of paper notes. One thing that had been very useful is to make (short, simple) indices in my paper notes and to digitize just the indices.
It takes almost no time. The result is that when I want to look at old noted I can look up where in my digital indices, and then walk over to a shelf and pick out my notes. I've used this *a lot* and it's surprisingly helpful.
Caveat: I'm a mathematician, so I have a lot of paper notes and half-baked ideas. So my paper notes often look more like a set of laboratory notebooks and not idle learning notebooks. I essentoally never look back on noted I take while learning some new subject.
I suffer from terrible memory retention because of ADHD, so I need to rely to external storage more than most people—yet after obsessing about note taking for a while I reached productivity enlightenment: I really do not need to remember and categorise most of my thoughts and notes. I produce millions of ideas every day, and I have, hopefully, other 50 years ahead of me of potentially interesting thoughts I might feel I want to remember, only to collapse under this ever-increasing weight of nonsense, of things that seemed important one day, and really were not in the grand scheme of things.
No, these days I write, seldomly, on a paper notebook. I embrace my terrible memory and use it as a tool, to aggressively cull every extraneous thought du jour. If it's important, it'll come up again. If it's truly important, it'll keep me awake at night. That is the real problem of digital notes: they never fade away.
The only things I keep in Org Mode are memories from decades ago I am sure I will want to reminisce about when I am 80. Like my family tree, the list of video games I loved as a kid, the important dates of my life.
I am using hundreds of sheets of paper at any given moment. Those I don't use, I archive in boxes(if they are important) or throw them away(after digitalising).
I travel a lot, so when I need some notes, I just print them again in color whenever I am.
I only process the notes automatically with an AI in order to search. But nothing sophisticated and storage is cheap so they remain a high quality image, I do not bother making it into a proprietary eink format(although I calculate it for searching).
I do not use the iPad for that, because paper and color pens give me way more real state for way less money and eink capabilities.