Hi Johannes
my recommended way to publish data to Industrial Edge especially when you want to insert them to Apps like IIH Essentials to publish it like a connector on Databus using MQTT in combination of the Common Databus Payload Format.
The usage of the common databus payload format is not difficult. You find the whole specification here:
https://docs.eu1.edge.siemens.cloud/apis_and_references/apis/databus/reference/index.html
You need to tell the IED app how to provide data to IIH Essentials. Perhaps there is already a connector available within the Edge/Siemens ecosystem?