We have a similar case, but it can't be fixed with the X-Dynatrace header since the NServiceBus handlers are defined as custom services (listeners) and do't start with an HTTP call. No Http, no headers, no linked purepaths.
I know we can solve this by using the DT SDK: https://github.com/Dynatrace/OneAgent-SDK-for-dotnet#trace-messaging
But can this also be achieved via OpenTelemetry? Since that's an open standard it would make more sense to us.