Deploying Gateways in GKE

I have deployed multiple applications on the GKE cluster using the same ingress. Gateway and Route resources will deliver more functionality not available in Ingress.
So, I want to replace the ingress with Gateway and HTTPRoute for allowing multiple namespaces.

First I am trying to deploy the Gateway with the same Namespaces
and I have replaced the ingress with the gateway and httproute.

SYNC on hello-gway/external-http is successful and Bind of HTTPRoute “hello-gway/hello-external” to Gateway “hello-gway/external-http” is working when I deployed gateway and httproute.

But the host is not working, it is showing 404 Not found. I am trying to understand why the host is not working when deploying the gateway and httproute instead of ingress.

gateway.yaml and httproute.yaml files

I would appreciate any help to debug this issue.

References:

Deploying Gateways | Kubernetes Engine Documentation | Google Cloud

Simple Gateway - Kubernetes Gateway API (k8s.io)