I use OneNote at work. It's the one Microsoft product I really enjoy using. It does so much and lets you organize things any which way you want. It is about as close as I've seen to digital paper.
Granted, I haven't had to do sketches in there, or any kind of OCR. I think I'd still do those on paper.
I've got one folder per project and one folder for each thing I want to learn.
Having EVERYTHING in one big text file would scare me a bit. I've been using the open source app Joplin which lets you take notes in Markdown and am leaning toward one folder per month and taking individual plain text notes there.
The metadata is in a database but the notes themselves are all plain markdown. If something bad ever happens to Joplin, I can just dump the .md files to a folder and move to something else.
I'm surprised to not see more Banktivity users. It's like Quicken with the option to do envelope budgeting. Unlike Quicken there is not a required yearly subscription fee, unless you want it to directly download your transactions from your bank. I prefer not to do that.
It does so much and the customizable reports and amount of info it gives you at a glance includes some things I don't see in other apps. Examples are savings rate (not present in any other app I've seen) and a calendar view of your finances (which is in a few apps, but not many)
Granted, I haven't had to do sketches in there, or any kind of OCR. I think I'd still do those on paper.
I've got one folder per project and one folder for each thing I want to learn.