Thank you for pointing this out.

Initially, I was facing problem while setting the URL, so I followed this recommendation, and it worked.

But yes, you're right, URL can change because of the suffix (1735). I used the --generate-name option while installing kube-prometheus-stack, as this option adds a unique suffix to the release name.

To avoid this, we can use a fixed release name "kube-prometheus-stack", instead of --generate-name. This will create a consistent service name: kube-prometheus-stack-prometheus

helm install kube-prometheus-stack --version {{ prometheus_stack }} prometheus-community/kube-prometheus-stack --create-namespace --namespace monitoring --values {{ ansible_user_dir }}/kube-prometheus-stack.values

With this, URL will always be:
http://kube-prometheus-stack-prometheus.monitoring:9090 as describe in this kube-prometheus-stack grafana datasource file also

I tried this approach, and it worked.