Almost. Your "wordpress" doesn't need any modification at all. Once netclient is running on your node(or all nodes via daemonset in cluster) and the wg interface to the netmaker server is up on every node, you can change your k8s cluster coredns to forward "."

kubectl -n kube-system edit cm coredns

to the netmaker server (and a backup server if you like). Then everything in your cluster will automatically use it. Wordpress and whatever else you have running. You can chain it then to. Let's say your k8s cluster(coredns) is configured to use netmaker as a forwarder for "." then you can set your netmaker server to forward to pihole for example. You don't need to worry about resolvectl in this case at all.