App lock and fingerprint
Under “App Security” set a passcode and optionally turn on biometric sign-in, which uses an Android Keystore key that requires strong biometrics.
A good password
Because your financial data is protected by a key derived from your password, a long, unique password is the most important thing you can do.
Devices
See the signed-in devices, remove an unknown one remotely and get an alert for every new device.
Screen privacy
By default the app window is protected from screenshots and from showing in Recents; you can change this in Settings. On the home screen the eye icon hides amounts.