solved the problem by using a
DummyTempratureSensor
unfortunately this device is not documented and especially setting the temperature was some kind of pain. But sourced showed of methods to update Temperature und Humidity analog to DummyThermostate
so with
http://pimatic.ip:8080/api/device/esp-test-hap/changeHumidityTo?humidity=50
http://pimatic.ip:8080/api/device/esp-test-hap/changeTemperatureTo?temperature=26
i was able to update the device with my esp sensors and the DummyTempratureSonsor is compatible to HomeKit.
I also discovered that even ESPimatic and nearly alle other self made ESP based sensors are using simple VariableDevices. That works but only when using the web frontend.
So for now it is possible for me to use my esp sensors with HomeKit