You can configure the minimum permission policies and trust policies for the IAM user and IAM role to generate the temporary security credentials for the Redshift IAM Role ARN. If you want EC2 instances to assume an IAM role to gain access to Amazon Redshift securely, use the temporary security credentials using AssumeRole for the Amazon EC2 role.

For more information about configuring an AssumeRole, see the following How-to-Library article: Configure AssumeRole authentication for Amazon Redshift V2 Connector

Generate the temporary security credentials based on your requirement.