Documenttation: https://docs.openshift.com/container-platform/4.15/installing/installing_vsphere/ipi/installing-vsphere-installer-provisioned-network-customizations.html#modifying-install-config-for-dual-stack-network_installing-vsphere-installer-provisioned-network-customizations

There is a red box where it suggests using a wait-ip nmstate parameter to make the connection wait for the presence of both an IPv4 IP and IPv6 IP. The problem is that this way to specify arbitrary nmstate settings is only available for baremetal platform, not vsphere.