In a VMware Cloud Foundation environment, the supported method to upgrade ESXi hosts for a vSAN stretched cluster is using vSphere Lifecycle Manager Images. This approach allows for a more streamlined and consistent way to manage the lifecycle of ESXi hosts within the cluster, ensuring that all hosts are compliant with the desired image. vSphere Lifecycle Manager Baselines are typically used for individual patching and updates rather than full upgrades, and vRealize Suite Lifecycle Manager is focused on managing vRealize Suite products and not vSphere or vSAN.