Yes, at my startup we run https://github.com/Place1/wg-access-server inside our kubernetes clusters to give engineers access to local pods vs the k8s DNS (*.svc.cluster.local). It works relatively well but we've had to make a couple modifications:

1. I had to deploy CoreDNS to our cluster and set up DNS query rewriting to redirect queries from *.cluster.mystartup to *.svc.cluster.local because docker on OS X has issues resolving hostnames that end in .local

2. I had to modify the code to support a non-standard MTU to deal with a networking issue related to google cloud.

Not plain Wireguard, but I've set up Tailscale with a proxy container + their MagicDNS pointed towards the kube-dns pod (running on GKE Autopilot).

It works like a dream and was dirt simple to set up, but would probably require some additional work once you go beyond one cluster (which I think is true for cross-cluster service discovery regardless in Kubernetes).