Kubernetes performance impact or overhead on running applications
You can get some kubelet metrics from the Node Performance Dashboard. More information here
Here are some metrics for the kube-proxy.
And the network overlay performance will depend on the type of network overlay that you are using here are some for Calico comparing throughput with CPU usage.
You can also compare some of those metrics with profiling the running containers on your nodes using cAdvisor
Btw, on the later K8s versions the kube-proxy and overlay run in a container/pod.