@Kat246 hello, check if you have, by chance you have hidden apps. Access Settings / Home screen / Hide applications and check if they are hidden. Greetings.
"The quieter you become-the more you are able to hear..."
You have to do the factory reset of the phone. Back up all your data on Google drive or Samsung cloud before that. After the reset be carefull what apps u download. Change your Samsung and Google account passwords and set up two step verification on all accounts or download Authenticator app.
