This looks pretty nice. In the same space, personally, I'm a huge fan of Joplin. Apps for every platform I care about, and the ability to self-host the server component (which is what I do). I has some really nice features, like import/export of directories of markdown files, and sharing notebooks with other users.
Since Joplin's developer decided to put all Markdown files into a database and thus give up all the advantages of a flat file system, I have uninstalled Joplin. In my view, the last discussion in Joplin's forum on this topic further discredited the developer.
I'm interested in what advantages you have lost. Joplin allows you to export your entire notebook as a directory of markdown files (with front matter), and from a performance, reliability, and replication perspective, a database seems like a much better choice.