Well, Veeam ONE would be the perfect solution to this
Changes to repositories create an event. https://helpcenter.veeam.com/docs/backu ... ml?ver=120
You could create a tasks which sends an email each time this event is logged in Windows.
Or, use the Syslog Integration, and forward all events to a SIEM solution.
That's right, VBR itself doesn't have a built-in notification for those settings. From a security perspective it's better to have an external system monitoring security related events and settings. If a bad actor gains access to your backup and manipulates its configuration, notifications would probably also get disabled or altered.
So whether it's Veeam ONE, a SIEM solution or a regular monitoring software (or a combination), I would recommend to have it separate from VBR.