Hey there Jan,
From the Google Home app, if you tap on your device, you should get an option at the bottom of your screen to Stop casting. If you are casting from a Chromecast-enabled apps, you should also be able to press on the Cast button to disconnect as well.
Let me know if that's the answer you were looking for. If you still had any questions, please let me know!
Thank you,
Jeran
(Community Specialist)
