📖 follow up of update metrics documentation to bring more clarity #4358 (#4359)

Author: camilamacedo86

docs/book/src/reference/metrics.md

@@ -3,6 +3,7 @@
 By default, controller-runtime builds a global prometheus registry and
 publishes [a collection of performance metrics](/reference/metrics-reference.md) for each controller.
 
+
 <aside class="note warning">
 <h1>IMPORTANT: If you are using `kube-rbac-proxy`</h1>
 
@@ -11,10 +12,14 @@ Your projects will be affected and may fail to work if the image cannot be pulle
 
 **Images provided under `gcr.io/kubebuilder/` will be unavailable from early 2025.**
 
-- **Projects initialized with Kubebuilder versions `v3.14` or lower** utilize [kube-rbac-proxy](https://github.com/brancz/kube-rbac-proxy) to protect the metrics endpoint. Therefore, you might want to continue using kube-rbac-proxy by simply replacing the image or changing how the metrics endpoint is protected in your project.
+- **Projects initialized with Kubebuilder versions `v3.14` or lower** utilize [kube-rbac-proxy](https://github.com/brancz/kube-rbac-proxy) to protect the metrics endpoint.
+In this case, you might want to upgrade your project to the latest release or ensure that you have applied the same or similar code changes.
+
+- **However, projects initialized with Kubebuilder versions `v4.1.0` or higher** have similar protection using `authn/authz`
+enabled by default via Controller-Runtime's feature [WithAuthenticationAndAuthorization](https://pkg.go.dev/sigs.k8s.io/[email protected]/pkg/metrics/filters#WithAuthenticationAndAuthorization).
 
-- **However, projects initialized with Kubebuilder versions `v4.1.0` or higher** have a similar protection using authn/authz enabled by default via Controller-Runtime's feature [WithAuthenticationAndAuthorization](https://pkg.go.dev/sigs.k8s.io/[email protected]/pkg/metrics/filters#WithAuthenticationAndAuthorization).
-In this case, you might want to upgrade your project or simply ensure that you have applied the same code changes to it.
+If you want to continue using [kube-rbac-proxy](https://github.com/brancz/kube-rbac-proxy) then you MUST change
+your project to use the image from another source.
 
 > This infrastructure is outside of our control, we cannot guarantee any timeline or any extensions.
 > For further information, see: [kubebuilder/discussions/3907](https://github.com/kubernetes-sigs/kubebuilder/discussions/3907)