Enable Organizations trusted access and backup policies for AWS Backup. Configure the central account as the delegated administrator for AWS Backup. Create IAM policies and backup policies. Enable cross-account management. Create a backup vault in the central account. Create a KMS key for the backup vault and share the key with the production account. In the production account, restore the databases from a snapshot and apply the shared KMS key to the new DB instances. Create a backup plan in the central account to back up the databases to the backup vault.

Enable Organizations trusted access and backup policies for AWS Backup. Configure the central account as the delegated administrator for AWS Backup. Create IAM policies and backup policies. Enable cross-account management. In the production account, share the default RDS KMS key with the central account. Create a backup vault in the central account. Apply the shared default RDS KMS key to the backup vault. Create a backup plan in the central account to back up the databases to the backup vault.

Create an Amazon EventBridge rule to invoke an AWS Lambda function every day. Program the Lambda function to decrypt the snapshots and to initiate a copy request of all unencrypted snapshots to the central account. After the copy job is complete, create a new KMS key. Use the new KMS key to encrypt the database snapshots in the central account.

Create an Amazon EventBridge rule to invoke an AWS Lambda function every day. In the production account, share the default RDS KMS key with the central account. Program the Lambda function to decrypt the snapshots and to initiate a copy request of all unencrypted snapshots to the central account. After the copy job is complete, encrypt the database snapshots with the shared default RDS KMS key in the central account.