In the same topic there is also an explanation why recording system permissions and owners is difficult in Android.
For most apps that I installed explicitly - games, productivity apps, launchers and a lot more - backing up and restoring work fine.
For some system apps (which I did not install explicitly) some backups could not be restored on an upgraded Android. For example, after the upgrade from LineageOS 14 to LineageOS 15, OAndBackup could restore neither my contacts nor my WiFi access points nor my system settings. Generally, I’d recommend a separate backup of contacts and calendars - these are the most crucial data handled by system apps, in my opinion.
In some cases, restoring a backup worked fine after the upgrade (e.g. with Amaze file manager) but afterwards the app crashed because it needed to regain permission for accessing external storage (and with the restored backup the app knew that it had already asked for such, not knowing that I had upgraded the system in-between). In such cases, it is a good idea to first start the app on the upgraded system, let it ask for the permission, grant it and then restore the backup.