This guide might not be correct, i am sharing what works for me

Tools:
Jailbroken
installed OpenSSH
Connect to phone using Winscp (for windows)

Apps are located at
/var/mobile/applications

Real Example:
/var/mobile/applications/12345C48-86AA-45D7-BCAE-35C9B3112345/WhatsApp.app

You can backup all the folder inside
/var/mobile/applications/12345C48-86AA-45D7-BCAE-35C9B3112345/

Normally Saved Game Data/Setting are located in
/var/mobile/applications/12345C48-86AA-45D7-BCAE-35C9B3112345/xxxxxx/Documents/

After copying/restoring the files back to e.g /Documents/ rememnber to set its permission to 775 (right click on the files and choose properties in Winscp)

Good luck