Hi there,
GP doesn’t include Font Awesome by default anymore. If you’re still using the old Font Awesome 4 that was in GP, you can disable it by going to “Customize > General” and checking the “Load essential icons only”.
To add your child theme file, you can add this to your child theme functions.php file:
add_action( 'wp_enqueue_scripts', function() {
wp_enqueue_style( 'font-awesome-5', get_stylesheet_directory_uri() . '/fonts/fontawesome/css/all-min.css' );
} );