I also mentioned a few things I missed: recent file access and either a full-text search or quickly jumping to a heading in longer documents.
Turns out recent files can be accessed via the “+” Button at the bottom. Not very obvious a place to put this, but hey.
Also, jumping to headings is possible. Not from within the app by default, but through a custom action. In the 1Writer action directory, you’ll find “Jump to Section” by @Pgruneich. It shows a list of headings from which you can select, then it takes you there. That’s it.
Works great and makes the app even more useful. Go 1Writer!