Btw, if you'd like to follow the metrics implementation in the Node.js agent more closely, you can keep an eye on this GitHub issue: https://github.com/elastic/apm-agent-nodejs/issues/422
Just bear in mind that even when this issue is resolved and released, it doesn't necessarily mean that the metrics feature is available in the APM UI in Kibana yet (as we might release a feature in the agent some time before the Kibana release, or the Kibana implementation might be delayed for other reasons). But you can of course always create a custom Kibana dashboard in that case.