That's all perfectly sensible things to be concerned about. But given that we're talking about an android app - if you're eligible to use the app, Google almost certainly already has all your data anyways.
Yeah I'm sure there's a tiny subsection of the people in these discussion who have custom ROMs flashed, but the vast majority are posting about Google tracking them on a google phone - or (even more annoyingly) posting about it from a phone that doesn't even support the app, and so doesn't remotely affect them