Comment by mesotron_dev

Another way to solve this is to use Fossil. Fossil has a built-in wiki. You can launch Fossil UI and use the built-in wiki with Markdown. Have legacy txt files? Just open a new fossil project and add them to it. And if you set up the admin and user correctly, you can mirror your notes to GitHub. So, it's not that text files are not a good option. There are vastly superior options with almost no effort.