From an Azure Stack HCI 20H2 perspective, you have a few options - Windows Admin Center or System Center Virtual Machine Manager could be used to manage those clusters in each of the 5 locations, however the assumption there is, all 5 sites can be reached from your WAC/SCVMM machine.
In addition, when you register Azure Stack HCI to Azure, you can utilize Azure Arc to manage your clusters. We will be continuing to add additional management capabilities for Azure Stack HCI, to Azure Arc, as we go forward.
Thanks!