HA is on the dedicated hw, but I also set up another HA with docker into RPI. My desire: in case my old linux has any problem I could restore a backup on the RPI. The issue is: when I go the UI on google bakcup add on I cant see the backup. I manually copied the file from the backup drive on the linux to the folder on the RPI.
If you want to restore a back in Home Assistant OS that’s stored somewhere else, you can copy it to the /backup directory/share in your HA OS installation and reload as shown above, or simply upload from the UI via Upload backup from the same menu. I don’t have any experience with the addon that you’re using, but you would follow those instructions to get HA to restore a backup.