The solution for me as well was to create a new home with a new google profile. So it has to be some bad state on my main Google profile.
This is not ideal, but by sharing my new home with my main home, it kind of works. Not ideal, but Google Home is not my main smart home app, that is Homey of course.
I only use Google home for my Google Wifi, and to set up a Nest Mini for voice control of Homey Flows.
Thanks for the tip @Henk_Bartels.
