We have a stretched cluster (not vSan, but Nutanix hardware with ESXi hypervisor).

VM/Host Rules manage which side of the cluster the VM resides in. It works fine.

During patching or host reboots, it's possible for a VM to end up on the wrong side of the cluster and the DRS rules just send it back to the right side. VMs work find on the wrong side, it's just their compute/storage aren't physically local to each other any more.