A company is building a cloud-based application on AWS that will handle sensitive customer data. The application uses Amazon RDS for the database, Amazon S3 for object storage, and S3 Event Notifications that invoke AWS Lambda for serverless processing. The company uses AWS IAM Identity Center to manage user credentials. The development, testing, and operations teams need secure access to Amazon RDS and Amazon S3 while ensuring the confidentiality of sensitive customer data. The solution must comply with the principle of least privilege. Which solution meets these requirements with the LEAST operational overhead?