Hi Marco

Are you using managed or external tables?

This should be easily shown either in Unity Catalog, or by checking in your storage account if the folders are ID based or have actual table names (eg dim_customer or something).

either way I would move the data to the temporary storage layer using a deep clone. This ensures you keep all the internal references such as the delta log in Unity catalog - those will break if you simply copy the files in storage directly. 
since the solution is not that big the cost won’t be significant

https://docs.databricks.com/aws/en/delta/clone

main difference is the cleanup. For managed tables you can simply drop the tables/schemas in UC - for external tables you need to go and physically delete the files in the storage account