Docs detailing specifications for install-config.yaml parameters to be used for AWS have a difference with examples:
this doc
https://docs.redhat.com/en/documentation/openshift_container_platform/4.16/html/installing_on_aws/installation-config-parameters-aws#installation-configuration-parameters-optional-aws_installation-config-parameters-aws
states that these parameter exists
compute.aws.region
controlPlane.aws.region

but examples instead show that this parameter exists

platform.aws.region

When running the openshift create cluster a error is raised if these parameters are used

compute.aws.region
controlPlane.aws.region

and the installer reports instead that this one is missing

platform.aws.region