No need for AWS IAM users
It's long been considered "best practice" to avoid having IAM users in AWS. Where possible IAM roles are preferable as role session credentials are short-lived. As far as I can tell, the only justification for AWS IAM users that I hear nowadays is for usage on non-interactive systems outside of AWS (so AWS SSO won't work), e.g. a Raspberry Pi in your closet.
I created a proof-of-concept project cloudkey to show that even that
scenario can avoid IAM users. It uses the little-known iot:AssumeRoleWithCertificate
functionality to avoid that.