After writing the last post Note taking without note taking app, I found that manipulating documents via a minimal UI would be more efficient than via command lines. So in the past two weeks I learned Electron and wrote a app (current only for macOS), called Mole. Here is the homepage.
The app is not perfect yet, especially in performance. I already have some ideas in mind that could fix it. I have exported all my text notes out from other note taking / writing apps (wish this was the last time I did this kind of thing). From now on, I will continue use Mole myself, and improve it.