All my notes got deleted after changing the WebDAV URL!
When changing the WebDAV URL, make sure that the new location has the same exact content as the old location (i.e. copy all the Joplin data over to the new location). Otherwise, if there's nothing on the new location, Joplin is going to think that you have deleted all your data and will proceed to delete it locally too. So to change the WebDAV URL, please follow these steps:
While trying to connect to Joplin Server with WebDAV using rclone:
<3>ERROR : : error listing: couldn't list files: Internal Server Error: 500 Internal Server Error Failed to lsf with 2 errors: last error was: error in ListJSON: couldn't list files: Internal Server Error: 500 Internal Server Error
It seems that joplin-server stores everything in a database (including large files..?), thus server-side migration isn't easily possible either.
I think there should be a better migration process, especially to-from Joplin [Cloud] Server.