Block access from pgAdmin to Postgres in kubernetes

We are trying to setup a pgAdmin but want to avoid that the root user could connect and create, update or delete anything. We have create a new readonly-user for this case and this works fine. But it is still possible to create a server in pgAdmin with root data. Our idea was to block the connection for root but in kubernetes there are no static IPs for services. That means we cant block the root access without blocking the backend and keycloak. Are there any other concepts we are missing but very helpful for our usecase?