Some backup applications carry out the encryption process of the backups that are generated through them, with the ur backup application when this happens, since when making a backup, the files are moved in encrypted form to a destination storage but They are not encrypted with a password to make their storage more robust.
I believe encryption is being worked on, however your loose de-duplication support, i would think moving the server would also be high improbable once they are encrypted.
The ideal would be that when these encrypted backups are placed on the UrBackup server, the server can recognize them and request encryption credentials to be able to see the content of the backups, in this way it would be ensuring that the encrypted backups are not left behind. useless.