Network settings are very easy
Option 1 -> use DHCP -> nothing to configure
Option 2 -> use static IP -> configure IP, subnet and gateway manually
Ne need to restore from any backup.
Some other settings are stored in some files
/storage/.kodi/userdata/sources.xml
/storage/.kodi/userdata/passwords.xml
You can backup this files and restore after fresh install
Best way to get a stable installation -> fresh installing addons, skins etc.