Set up Cloud Logging and Cloud Monitoring with Cloud Functions to send an alert every time a new database instance is created, and manually validate the region.

Set up different organizations for each database type, and apply policy constraints at the organization level.

Set up Pub/Sub to ingest data from Cloud Logging, send an alert every time a new database instance is created, and manually validate the region.

Set up different projects for PostgreSQL and MySQL databases, and apply organizational policy constraints at a project level.