/**
 * Remove the Categories widget if current logged in user isn't editor or admin
 */
add_filter( 'streamtube/core/post/edit/taxes_not_included', function( $taxes_not_included, $post_id ){
    if( ! current_user_can( 'delete_others_pages' ) ){
        $taxes_not_included[] = 'categories';
    }
    return $taxes_not_included;
}, 10, 2 );

/**
 * Change the Tags label to Categories
 */
add_filter( 'streamtube_core_the_field_control_args', function( $args ){
    if( current_user_can( 'delete_others_pages' ) ){
        return $args;
    }
    if( array_key_exists( 'name', $args ) && $args['name'] == 'tax_input[video_tag]' ){
        $args['label'] = esc_html__( 'Categories', 'streamtube-core' );
    }
    return $args;
}, 10, 2 );