Trouble creating child theme of Charitize Pro

I’ve followed the steps in https://developer.wordpress.org/themes/advanced-topics/child-themes/ and tried numerous variations on the code there but can’t get the child theme (which is still basically empty at this point) to load properly. The menus I’ve created are shown but none of the other Appearance settings or other customizations that I’ve made, instead it shows the default theme images etc. Everything returns to normal when I switch back to the parent Charitize Pro theme.

Is there anything special I need to do for this parent theme?

Here’s an example of what I’ve tried in functions.php:

add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles' );
function my_theme_enqueue_styles() {
    $parenthandle = 'charitize-style'; // This is 'twentyfifteen-style' for the Twenty Fifteen theme.
    $theme = wp_get_theme();
    wp_enqueue_style( $parenthandle, get_template_directory_uri() . '/style.css', 
        array(),  // if the parent theme code has a dependency, copy it to here
        $theme->parent()->get('Version')
    );
    wp_enqueue_style( 'charitize-child-style', get_stylesheet_uri(),
        array( $parenthandle ),
        $theme->get('Version') // this only works if you have Version in the style header
    );
}

Thanks a lot!
Alex