I have found a way to make this work. I have Homebridge running Apple TV Enhanced as a plug-in and thus exposed in HomeKit. After that I have used HomeKitty to create switches. These switches I have used in a Flow to have my desired scenes set up. Then I went back to Homekit to create automations. Apple TV Enhanced are used as trigger and from there I triggered the HomeKitty flows with the desired scenes.
I hope this is somewhat clear, if not feel free to let me know.
Maybe I can share my Flows if this is interesting to get the mind set going.