When you simply factory reset your Android phone, it remains associated with your Google account. There's a way to avoid that ...

Go to Gemini Settings > Personal Context to see for yourself. There is a toggle for Your past chats with Gemini for Gemini’s ...

When you tap delete on your Android phone, a file might disappear from your view. But it's not really gone. You've erased the index of that file, but the file itself is still in the phone's storage.