Elastic APM. As far as I am aware it's an implementation of the OpenTracing specification.

We just use the Elastic client libraries. Tell it where our APM server is, do the little bit of application set up and then view all our application traces in Kibana.

All applications follow the same basic setup. Probably less than 20 lines of code and then wrapping some HTTP handlers and HTTP clients. Then we have some application specific spans.

Any plans to switch to Opentelemetry?

Not that I know of

Personally, I am using Opentelemetry to create and export my distributed traces. At first sight it looks like they have reinvented the wheel for this project.