I note that in Google Settings, when I try to go to Mobile data & messaging, it doesn't know my phone number. That leads to me to believe that the functions in Google Settings are simply installed because of GFS but not functioning. However, under Advertising ID, it does have an active ID number (although it can be deleted and opted out of). I don't know how Advertising ID usually works on Android, but I assume it is something like this: an app that wants to show an ad looks up your advertising ID, then sends data to Google, and Google sends back a personalized ad. Furthermore, for the ID to be useful, it must be associated with your Google account, and Google must be associating it with all the location data, browsing data, etc, it collects on you.
In GrapheneOS with Sandboxed Google Play, is this ID number essentially a dumby, sitting there not doing anything? Or, if we sign in to Google Play Store, will that number get associated with that account? Or, if we initialize Google Play Store but don't sign in, will that number get associated with random data that Google collects from our phone (like if we use Google geolocation services) but without a Google account?
Also, is there any reason not to turn off personalized Advertising ID in Google Settings?