Hello,
I believe the best available approach for backup is to provision from the beginning your organizational infrastructure using Meraki Terraform provider. This approach ensures that you consistently maintain a clear picture of what's deployed under the Terraform state file. Consequently, if any manual changes occur, you can simply execute Terraform apply across your organization's setup to restore it effortlessly.
Alternatively, you can opt for Meraki third-party tools to manage your backup needs.
Please let me know if this addresses your concerns.