Manage multiple region application in Well-Architected workload

You should not couple your regions together or you will lose one of the primary benefits of multi-region deployments: the ability to operate independently. Please read https://docs.aws.amazon.com/whitepapers/latest/aws-fault-isolation-boundaries/abstract-and-introduction.html

In this case, you should ensure the templates are stored in buckets in each region and use the service catalog service in that region to deploy. There is likely much more than that in your concerns.