Hello @halkhamis
If you want to use an external database with Freescout you will have to fork the Freescout package and change it so that you can use an external database.
It sounds like you want to use enterprise and high availability features for a software that is not highly available in the first place, so the HA of the DB will offer nothing when the software is down anyway.
Cloudron also provides the security and encryption for the DB and also offers the backup and restore for the app and database itself, but not PITR.