anonymous user ,
Thanks for reaching out to Q&A.
You have already enabled sampling which would filter the telemetry data. maxTelemetryItemsPerSeconds would target number of telemetry items logged per second on each server host. If your app runs on many hosts, reduce this value to remain within your overall target rate of traffic. So you can revert back to the default setting of 20.
You can try to set the "Function" to "Warning" and see if that makes a difference. You should still see your custom logs. Please try and let me know the outcome.