They don't know who is talking to whom, that metadata is encrypted. All they know is the last time you were online, the date you signed up and your phone number. (Fair last one may be an issue) We've seen this tested again and again.
I would consider anything other than GrapheneOS a scam or even a honeypot at this point. Braxman is a complete utter joke, this crap is no different than that MAGA guy selling his freedom phone or whatever it was called.
The idea that US apps are somehow better than Chinese apps when it comes to collecting and selling user data is complete utter propaganda.