remove metabox is not working for wp 5.7

Hi I am using wordpress 5.7 and Vidio theme, Here the theme have some plugins with it. Those plugins create a metabox with id haru_video_attached_directors. I want to remove this metabox from custom post type haru_video for that I used wp function remove_meta_box(put in child-theme functions.php) but not getting success. I have already followed the similar questions and added almost every hook but still not getting the desired output.

function remove_metaboxes() {    remove_meta_box( 'haru_video_attached_directors' , 'haru_video' , 'normal' );    remove_meta_box( 'haru_video_attached_directors' , 'post' , 'normal' ); } add_action( 'admin_head' , 'remove_metaboxes' ); add_action( 'admin_menu' , 'remove_metaboxes' ); add_action( 'admin_init' , 'remove_metaboxes' ); add_action( 'wp_dashboard_setup', 'remove_metaboxes', 20 ); 

Code present in Plugin

$  video_submit->add_field( array(         'default_cb' => 'haru_maybe_set_default_from_posted_values',         'name'    => esc_html__( 'Attached Directors', 'haru-vidi' ),         'desc'    => '',         'id'      => 'haru_video_attached_directors',         'type'    => 'custom_attached_posts',         'column'  => true, // Output in the admin post-listing as a custom column. https://github.com/CMB2/CMB2/wiki/Field-Parameters#column         'options' => array(             'show_thumbnails' => true, // Show thumbnails on the left             'filter_boxes'    => true, // Show a text box for filtering the results             'query_args'      => array(                 'posts_per_page' => 10,                 'post_type'      => 'haru_director',             ), // override the get_posts args         ),     ) );