Uninstall apps that have a web app, particularly if you use it rarely.

Some phones have an option to make the display black and white either all the time or on a schedule (at night)

Disable notifications for apps that aren’t important. Set less urgent app notifications to “silent” so they don’t pop up.

Disable email notifications entirely.

Set your phone to silent when you’re not expecting important notifications.

Prevent the screen from turning on when notifications appear.

Go through every single setting on your phone, carefully consider each one, and choose the less intrusive / distracting option.

Relatedly, I’ve also written up what I’ve done to make Android a bit more private.