Run application code with AWS account root user credentials to ensure full access to all AWS services

Create an IAM role with an AmazonDynamoDBReadOnlyAccess policy and apply it to the EC2 instance profile

Create an IAM user with Administrator access and configure AWS credentials for this user on the given EC2 instance

Create a new IAM user with access keys. Attach an inline policy to the IAM user with read-only access to DynamoDB. Place the keys in the code. For security, redeploy the code whenever the keys rotate