A healthcare startup is building a cloud-based patient management system on AWS. The system processes sensitive health data and uses Amazon RDS for the database, Amazon S3 for storing medical reports, and AWS Lambda for processing event-driven workflows triggered by S3 Event Notifications. The startup uses AWS IAM Identity Center to manage user authentication. The development, testing, and operations teams need secure access to RDS and S3 while ensuring compliance with healthcare regulations that mandate least privilege access and centralized access control. Which solution meets these requirements with the LEAST operational overhead?