As someone who manages a production cluster, I spend about 1% of my time worrying about the control plane. It’s trivial to get it running and keep it running now. It’s all the stuff you build on top of k8s that’s the hard part. I don’t see much value add to eks, personally.
Do you use something like kops for setting up and maintaining your cluster?
Most of my direct experience with Kubernetes has been on GKE, but I have been meaning to work through https://github.com/kelseyhightower/kubernetes-the-hard-way to gain more appreciation for what is going on behind the scenes.