Hi Eric,
As mentioned by Salah, you can just back-up and restore your database through SQL if you're using BC On-premise.
But if you're using cloud environment, there is no way of restoring Sandbox to Production, just Production to Sandbox.
Export a Data File and Import a Data file should have been the best option for this but it is not working and seems to be restricted by Microsoft. We can only utilize Config packages to do this.
I would suggest to just use the Copy company and set-up your initial configuration in the production environment, maximize the Copy company under company list page, to replicate the set-up and use it as Sandbox company within the same production environment but make sure to restrict the test company access only to the users through permissions. You can maximize your Sandbox by using it to deploy and test extensions/customizations before deploying to the Production environment.
