RDS AUTOMATIC BACKUP

As documented, to disable automated backups

Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/

In the navigation pane, choose Databases, and then choose the DB instance or Multi-AZ DB cluster that you want to modify.

Choose Modify.

For Backup retention period, choose 0 days.

Choose Continue.

Choose Apply immediately.

Choose Modify DB instance or Modify cluster to save your changes and disable automated backups.