Implement a “Reset All Settings” button in the settings tab, as a user should be able to return all settings to their initial values, like when they first installed the app.
The reason is that there are many things to change within settings, such as Autofill, default domain, security and there’s no way of knowing what the default settings were previously.
For a baseline, there should be a “Reset all settings to default” so that when a user does change any setting, they don’t get overwhelmed by thinking they’ve ruined the way the product works and can’t go back to the default settings easily.