Hi @hklages,
I wish you a happy new year too, although it is probably a bit early 
Finally got it working, after setting up everything from scratch. Had hoped to find some troubleshooting tips, to improve the smarthome node. Those guys have really done impressive development work to get this working. Don't know how they find their way in the complex Google API's...
But lost a lot of precious time "again". Had planned to finish a series of my new nodes during my Christmas holdidays, but that won't be possible anymore (although that might be a perfect solution for most people). Hopefully 2022 will become a better open-source year: my nodes were downloaded 205000 times in 2021, but I only received 1 major pull request. I cannot hide that I am very disappointed about that ... Although I must admit that the core of this community is VERY active and helpfull!!! A real joy to work together with them. Want to thank @Paul-Reed for all the time he has spend to help me with my Google Assistant problems!!
Until now I have been spending all my free evenings to try to do it 100% with Node-RED. Because personally I don't like to start linking multiple tools together. Will try to continue a bit further, but if things don't speed up soon with my personal home automation system (purely with Node-RED) I won't have much other choice than going that route. But that would mean that I would have to go for 100% HomeAssistant, which would be a pity for all the time I spend on my Node-RED developments so far.
But now we are way off-topic. My Google Assitant integration "seem" to be working now. So I am going to rework some of my flows, and then hopefully the entire familly can enjoy voice control in my house...
Case closed!
