Managed Postgres and backup data physical location

For our application state regulators require us to state in writing where our records and their backups are physically stored. We currently set the database (and Tigris) to a U.S. region but for the Postgres backup it’s not clear where the backup data resides. If we can’t verify both as stored in the same region, we’ll probably have to move to a platform that can provide these assurances.

for Managed Postgres in US the backups are stored in AWS us-east-1 (for east coast Fly regions) and AWS us-west-2 (for sjc/lax).

Thanks for the response. That would certainly work for our application. Is this documented somewhere such that I can reference as part of state due diligence?