Hide My Account in Napili Community

If you select the appropriate scope in your CSS, you can hide options in the Profile Header component:

For the profile menu option:

.profile.uiMenuItem{
    display: none;
}

You can modify the CSS under the branding options

However, this will affect all your users.

If you would prefer this to change based on profile (your admins might want to be able to access profiles easily) You might want to use Custom Theme Layouts, the feature is documented here