How would one scale the PV/PVC of a statefulset deployed via helm/pulumi? Changing the storage value in the statefulset is ignored (not even a replace which is probably a good idea :))

I guess this is not a pulumi issue, regardless of how you edit the STS the volume template change does not kick in. You can still expand the PVC by setting the new size and restart the pod. Automating this would nice though. For me expanding the PVC size is a very seldom operation so I do this part manually. Plus keep in mind you have to restart the pod for the volume expansion to kick in (EBS on AWS)