Best backup strategy (apks and app data)? I would like to backup my phone a regular basis. TWRP provides a full system backup and recovery option. This is fine but too inflexible for me and bound to the phone itself. 

I want to backup all apks and its' data from a running system (not recovery) and restore it back to the/different phone(s) with different Android Versions (6, 7.1). 

This is what i already did: As far as i can say. It doesn't work.

adb backup -f /path/to/backup-file -apk -shared -all -nosystem
adb restore /path/to/backup-file
Titanium Backup would be best option, you can have scheduled backups and it has worked consistently for years on my devices. Another option would be Helium by ClockworkMod but both apps require premium to use the automatic backup option.