> better separation of work/private notes (like different storage locations)

FYI, as of last year, Joplin supports profiles on both Desktop and Android that are exactly that. Though you do have to restart the app to toggle between the two.

Release notes: https://joplinapp.org/news/20220606-release-2-8/

Open issue for multiple instances ala Firefox: https://github.com/laurent22/joplin/issues/591