Hello Tobias,
I use OpenHab a central hub for all my different devices, so I have integrated Tradfri, Alexa, Homematic, Squeezebox, and many other sensors other mqtt in one central place.
Therefore I have connected Alexa to OpenHab and I can command per voice any of the system connected to OpenHab.
The CCU is only use as bridge between OpenHab and the Homematic modules.
I have computer science background, so it is not a problem for me to program rules and define the items directly in the files.
With Alexa I almose don’t use anymore the Basic UI but I use HabPanel with Raspberry and Touch Display.
I use the Hue Binding to connect to Alexa.
Best Regards
Jean-Claude