I write everything in markdown, and I mean just about everything. Tech notes, recipes, work procedures, shopping lists…everything. If you check my comment history from today, you can see a quick example of the kind of tech notes I keep (firewalld in this case).
I keep all of my plain text files synced across multiple devices using Syncthing. For desktop editors, I use mostly vim and VSCodium (though Kate is nice too), and I use Markor on Android. This workflow has been highly efficient for many years now, and I no longer waste time constantly reviewing the latest note-taking app.
If our children were still children, we’d probably have a Kids folder too.