I'm not aware of this having been done, but it would be unsurprising. You can't win against the OS... If the OS (or hardware) is malicious, you're out of luck. Nothing you can do as a developer. The OS has complete control...
If this is your major concern, I suggest moving to a deGoogle'd OS. There's still going to be concerns even after wiping Android because there's hardware, but certainly this places trust less in the hands of Google (but you're still going to need to trust the OS maker).
Registration is fair. There's been a lot of pushback against this. Things look to be moving in a positive direction with usernames, but hasn't quite come to removing phone number requirement. I believe they are still using this to help reduce spam (much easier to spam if email or no outer registration. But I hope they resolve that).
If this is your major concern, I suggest moving to a deGoogle'd OS. There's still going to be concerns even after wiping Android because there's hardware, but certainly this places trust less in the hands of Google (but you're still going to need to trust the OS maker).
Registration is fair. There's been a lot of pushback against this. Things look to be moving in a positive direction with usernames, but hasn't quite come to removing phone number requirement. I believe they are still using this to help reduce spam (much easier to spam if email or no outer registration. But I hope they resolve that).