Offsite Backup advice, please

How do I create offsite backups on the My Cloud EX2 Ultra NAS device via attached USB harddrives? [2tb - 4tb]

I am able to do this with my older My Cloud which is running v04.05.00.237 firmware using the SafePoint function. I have become quite dependent on the ability to take periodic total backups to by lock box at the local bank.

I am considering replacing my older device due to its age, etc.

By offiste backup, I mean a full backup of the complete data storage. No, it is not acceptable to backup shares individually.

If no practical method exists, I would appreciate advice on a practical NAS system to use. I have read interesting things about the Synology DS220+.

The My Cloud device features an ability to backup the data stored on its shares or sub-directories located within shares to a USB attached device.