Sounds like OpenTelemetry will really help make your life easier. We will post examples and documentation, including discussion most important metrics.
In the mid-time, when using Pump, the data we can export is documented here: GitHub - TykTechnologies/tyk-pump: Tyk Analytics Pump to move analytics data from Redis to any supported back end (multiple back ends can be written to at once).. However I don’t see the api_key listed as part of the export options in the documentation of the DogStatsD. Each Pump integration might have different options.
One other resource for you: a blog post about SLO/SLI and RED metrics using Prometheus Pump: Service objectives for your APIs with Tyk, Prometheus & Grafana
I hope this helps!