Standard VPC design template to provision VPC for the sandbox account

An alternative to Ronalds correct question, is if Account Factory doesnt give enough granular control and you wish to have multiple VPC's in a sandbox account, you most likely will need to explore Service Catalog https://aws.amazon.com/servicecatalog/

Here you can define "templates" and allow users to create resources using your IaC templates to ensure each resource created aheres to a standard

thank u so much buddies!