NetworkPolicy does not allow egress on HTTP/HTTPS ports
Turns out the policy I gave works fine, it's just that the controllers implementing the policy had some bugs. On Minikube+Cilium it just didn't work for IPv6 but worked fine for IPv4, and on AKS the feature is still generally in beta and there are other options that we could try. I haven't found anything on my specific issue when using the azure-npm implementation but since it works fine in Minikube on IPv4 I'll assume that it would work fine in Azure as well once a "working" controller is set up.
Some resources I found for the Azure issue: