Hi EPNAdam,
We can apply Azure policy to restrict or audit resource groups if they don't follow any naming convention.
resource groups with naming conventions like these .. AzureBackupRG_westeurope_1 are created by Recovery Service Vaults to create and store restoredpoints of VMs that are being backed up and they are automatically created by them.
We can control the naming convention of these RGs created by RSV from the option below though.
You can either update the RG name as per your requirement here or apply Deny policy so that whenever RG is being created by RSV, the policy will deny the RG creation request and user will be asked to update the RG name here with the required naming convention.