kubectl get tanzukubernetescluster -A N/A for phaseTMC
vSphere 8
This is due to the change of moving from v1alpha3 to v1beta1 where tanzukubernetescluster is being retired. New clusters are deployed with cluster so the previous API's are not applicable anymore.
This is working as designed. Eventually tanzukubernetescluster will be retired, but this is not an option with Tanzu Mission Control currently. When this option is available Tanzu Mission Control will publish further information.