This would make a great comparison. I'm not certain whether or not K8's mutual auth supports session ticket resumptions and distribution of short lived ticket keys. The ticket rotation design would probably make a great addition to K8. There are a lot of intricate details in design which can make a major difference in not only performance but also whether or not the system wakes you up at night.
My point was encryption of services is built into K8s/service mesh and wondering how it fares compared to FB's approach.