You can use firefox. Or degoogled andoid rom. Google spies on your phone mostly through their apps: chrome, maps…
Andoid by itself is very privacy focused operating system.
Check c/degoogle on how to remove google stuff from your phone. Also check privacy guides about vpns: https://www.privacyguides.org/en/vpn/
They are mostly not what they are advertised as. You should check tor. And maybe /e/os
Who said anything about teenagers? Kids too young to be left without supervision can now learn independence. So kids can be more independent at younger age compared to “good old times”!