[Zerif Lite] Remove Zerif Widgets from Admin Panel

Hello Support,

I want remove unneeded widget clutter from my Zerif Child Theme. As per WordPress manual, this code used in my child’s functions.php should do the trick, but it does not – The Zerif Widgets and Widget Areas still show up in the admin panel:

Someone please provide assistance how to get rid of the Zerif Lite Widgets and Widget areas, so they do not show up in admin panel anymore.

function kill_zerif_widgets(){
unregister_sidebar('zerif_ourfocus');
unregister_sidebar('zerif_testimonial_widget');
unregister_sidebar('zerif_clients_widget');
unregister_sidebar('zerif_team_widget');
}
add_action( 'widgets_init', 'kill_zerif_widgets', 11 );

Here’s my complete child functions.php, in case someone needs to see it to identify and solve the problem:

<?php

// Child Theme Loader (Loads functions.php from Zerif-Lite)
add_action( 'wp_enqueue_scripts', 'child_enqueue_styles',99);
function child_enqueue_styles() {
$parent_style = 'parent-style';
wp_enqueue_style( $parent_style, get_template_directory_uri() . '/style.css' );
 wp_enqueue_style( 'child-style',get_stylesheet_directory_uri() . '/custom.css', array( $parent_style ));
}

if ( get_stylesheet() !== get_template() ) {
add_filter( 'pre_update_option_theme_mods_' . get_stylesheet(), function ( $value, $old_value ) {
	 update_option( 'theme_mods_' . get_template(), $value );
	 return $old_value; // prevent update to child theme mods
}, 10, 2 );
add_filter( 'pre_option_theme_mods_' . get_stylesheet(), function ( $default ) {
	return get_option( 'theme_mods_' . get_template(), $default );
} );
}

/**
* Unregister some of the Zerif sidebars
* This code doesnt work. Zerif widgets still there
*/
function kill_zerif_widgets() {
unregister_sidebar('zerif_ourfocus');
unregister_sidebar('zerif_testimonial_widget');
unregister_sidebar('zerif_clients_widget');
unregister_sidebar('zerif_team_widget');
}
add_action( 'widgets_init', 'kill_zerif_widgets', 22 );

/**
* Register my own content areas.
* This code works as inteded, new widgets show up in WP-Admin
*/
function ftk_contentwidgets_init() {

register_sidebar(array(
	'name'=> 'Fortek Title/Header',
	'id' => 'ftk_title',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek Products & Services',
	'id' => 'ftk_focus',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek About Us',
	'id' => 'ftk_aboutus',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek Team',
	'id' => 'ftk_team',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek Contact',
	'id' => 'ftk_contact',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek Ribbon',
	'id' => 'ftk_ribbon',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

register_sidebar(array(
	'name'=> 'Fortek News',
	'id' => 'ftk_news',
	'before_widget' => '',
	'after_widget' => '',
	'before_title' => '',
	'after_title' => '',
));

}
add_action( 'widgets_init', 'ftk_contentwidgets_init' );
?>