Hi, I'm Elise, a fellow user like yourself and I'd be happy to help with your issue.
When it comes to server backups the goal is usually that you can restore the backup to another device quickly and easily if needed, along with if a user accidentally deletes a file, you can restore it etc,
I would recommend looking at third party backup solutions, that can take images of the device and can be restored quickly and easily.
If you use file history you will basically have to reinstall Windows server and reconfigure it all in the event of a failure, then restore the files from file history. It won't be painless in a failure situation.
Please let me know if you need any further assistance.
Kind Regards,
Elise