EC2 Instances should not have a public IPv4 address

Is the tool being used here Security Hub? If it is then this is addressed in https://docs.aws.amazon.com/securityhub/latest/userguide/ec2-controls.html#ec2-9

If you have a legitimate use case to maintain EC2 instances with public IP addresses, then you can suppress the findings from this control.

Details on how to suppress findings are here https://aws.amazon.com/blogs/security/how-to-create-auto-suppression-rules-in-aws-security-hub/