Here I send FPS values of a camera. It works, I build a graph, but I'm concerned about logs are not designed for it. And I cannot send many values in one request to lower traffic. Is it a right way to visualise a data of a variable?
This looks fine to me. The Elasticsearch documents will have a similar structure to the metrics that Elastic APM agents produce.
You could also index documents directly into Elasticsearch, and use the bulk API to reduce the number of requests.
I'm not sure if I undestood you... Will I be able to build a graph (line or gistogram) using API you described? What you mean "automatically"? I can write some SQL to visualise the data, it's not a problem. Or I can build only some types of graphs?
I just meant that there are no pre-built dashboards where your custom metrics will show up. You will have to create your own dashboard/visualisation. It sounds like you already intended to do that.