Joplin isn't that easy to setup for family. It also doesn't work like that for Dropbox, it links to a specific app folder on your own account. I'm also not sure

Joplin isn't that easy to setup for family. It also doesn't work like that for Dropbox, it links to a specific app folder on your own account. I'm also not sure about distributed editing it would result in a lot of conflict notes that you manually must fix. Just use Notion or Google Drive folder with docs if you don't have too many notes.