Run multiple WordPress instances in your Kubernetes cluster. Use internal or external database. Internal database means a single pod with MariaDB without any replication or clusterization, my WordPress operator is NOT MySQL operator. If you need database high availability use MySQL operator to create cluster.
Fortune cookie: "For my part I would not kill my wife, even if commanded to do so by the real God of this universe." [Robert G. Ingersoll, "Some Mistakes of Moses", 1879]