Alen lee
When it comes to smartphones there is nothing cofidential about any of them, especially if it is a android. Google the manufacturer and your cellphone carrier monitor everything you do to target you for advertising.
NEVER do anything financial on a smartphone, don't keep any files, and never ever enter or speek any of your important financial account numbers into any smartphone the open operating platform of a android phone makes it too easy to hack into!
However if you turn off your location history and your web activity, then use your private mode everytime you use the internet, you might get the privacy you seek!