that advise just restores the clean box to the same dirty state as when you did the backup #fail
take the backup, but DO NOT RESTORE IT
Instead extract/unpack the archive somewhere else and then stop Kodi (systemctl stop kodi) before selectively moving back the configuration items that you need. These are probably the guisettings.xml file, database files, and configuration in /storage/.kodi/userdata/addon_data/ - once done restart Kodi (systemctl start kodi) and rinse/repeat until things are back to normal.