How to monitor elasticsearch cluster itself using apm server?

I have spun up a 9 node Elasticsearch cluster 3 master, 3 data hot and 3 data warm in an EKS using Elasticsearch operator and i want to monitor these nodes using apmserver. So using the operators i configured below versions in my Kubernetes cluster
Kibana version: 7.15.1

Elasticsearch version: 7.15.1

APM Server version: 7.15.1
All the above pods are Up and running.
So I am able to access kibana, but not finding any apmserver or metrics in the apm section in kibana
My requirement is to monitor the Elasticsearch cluster itself. To do that do i need to make any changes in the cluster?, i saw apm-agents need to be installed in the nodes which needs to be monitored, Kind: Elasticsearch will spin the ES nodes which will have the apm-agent installed by default? How can i do that if Someone able to guide will be helpfull?

As your requirement is only to monitor the Elasticsearch cluster, I suggest you look at Stack Monitoring: Elasticsearch Monitoring Metrics | Kibana Guide [7.15] | Elastic

Instrumenting Elasticsearch with APM is not currently supported.