Thanks for your input! I managed to find the issue. The parameter values were in fact not set correctly.
May I ask another follow up question:
I now set up the FMOD project with the Oculus Spatializer and everything works in Unity.
When I build the game for the Oculus Go I come across an issue. It builds fine without any errors and installs the apk on the Oculus Go but when the app starts no sound is played.
What could be the issue of that?
Here are my audiomanager settings:

(I tried with and without setting the “Spatializer Plugin” to “OculusSpatializer”)
The oculus camera also has a fmod event listener component added.