Не сохраняется категория для слайдера

Дорое время суток!
В админке выбираю категорию для показа в слайдере «без категории» Ее ID — 1. Но настройка не сохраняется. Тема установленная на сайте платная, но используется free-версия. Как прибить категорию «без рубрики» гвоздями помимо админки?
Вот код:

	function color_blog_front_slider(){
		$color_blog_section_slider_option = get_theme_mod( 'color_blog_section_slider_option', false );
		if( false == $color_blog_section_slider_option ){
			return;
		}
		$color_blog_section_top_featured_posts_option = get_theme_mod( 'color_blog_section_top_featured_posts_option', true );
		if( true === $color_blog_section_top_featured_posts_option ){
			$slider_class = 'has-featured-slider default-width--slider';
		}else{
			$slider_class = 'no-featured-slider full-width--slider';
		} ?>
			<div class="front-slider-wrapper <?php echo esc_attr( $slider_class ); ?>">
				<div class="mt-container">
					<div class="front-slider-block">
						<div class="front-slider cS-hidden">
						<?php
							$slider_cat_slug = get_theme_mod( 'color_blog_section_slider_cat', '' );
							$slider_args = array(
								'category_name'    => esc_attr( $slider_cat_slug ), 
								'meta_key'     => '_thumbnail_id',
								'posts_per_page' => 7
							);
							$slider_post_query = new WP_Query( $slider_args );
							if( $slider_post_query->have_posts() ):
								while ( $slider_post_query-> have_posts() ): 
									$slider_post_query -> the_post();
									$post_id = get_the_ID();
									$image_url = get_the_post_thumbnail_url( $post_id, 'large' );
									if( !empty( $image_url ) ) {
										$slider_style = 'style="background:url('. esc_url( $image_url ) .') no-repeat scroll center center; background-size:cover"';
									} else {
										$slider_style = '';
									}
						?>
									<div class="slider-post-wrap" <?php echo $slider_style; ?>>
										<div class="post-thumbnail">
											<a href="<?php the_permalink(); ?>"></a>
										</div>
										<div class="post-info-wrap">
											<div class="post-cat"><?php color_blog_article_categories_list(); ?></div>
											<div class="entry-meta"> 
												<?php 
												color_blog_posted_on();
												color_blog_posted_by();
												?> 
											</div>
											<?php the_title( '<h3 class="entry-title"><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">', '</a></h3>' ); ?>
										</div><!--.post-info-wrap -->
									</div><!-- .slider-post-wrap -->
							<?php
								endwhile;
							endif;
						?>
						</div><!-- .front-slider -->
					</div> <!-- .front-slider-block -->
			<?php
					if( true == $color_blog_section_top_featured_posts_option ){
						$color_blog_top_featured_posts_title = get_theme_mod( 'color_blog_top_featured_posts_title', __( 'Featured News', 'color-blog' ) );
						echo '<div class="top-featured-post-main-wrapper">';
							if( !empty( $color_blog_top_featured_posts_title ) ){
								echo '<div class="features-post-title">'.esc_html( $color_blog_top_featured_posts_title ).'</div><!-- .features-post-title -->';
							}
								
								$color_blog_top_featured_post_order = get_theme_mod( 'color_blog_top_featured_post_order', 'default' );
								$top_featured_post_args = array( 
															'post_type' => 'post',
															'posts_per_page' => 5, // Количество слайдов
														);
								if( 'random' == $color_blog_top_featured_post_order ) {
									$top_featured_post_args['orderby'] = 'rand';
								}
								$top_featured_post_query = new WP_Query( $top_featured_post_args );
								if( $top_featured_post_query -> have_posts() ):
									echo '<div class="top-featured-post-wrap">';
										$featured_post_count = 1;
										while( $top_featured_post_query -> have_posts() ): $top_featured_post_query -> the_post(); ?>
											<div  id="post-<?php the_ID(); ?>" class="mt-single-post-wrap clearfix">
												<div class="post-thumbnail">
													<span class="post-number"><?php echo absint( $featured_post_count ); ?></span>	
												    <figure style="background: no-repeat center top url(<?php echo get_the_post_thumbnail_url(); ?>); background-size: cover; height: 100px;">
													</figure>
												</div>
												<div class="mt-post-content">
													<div class="entry-meta">
														<?php 
															color_blog_posted_on();
															color_blog_posted_by();
														?>
													</div>
													<header class="entry-header">
														<?php the_title( '<h3 class="entry-title"><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">', '</a></h3>' ); ?>
													</header><!-- .entry-header -->
												</div>
											</div><!-- #post-<?php the_ID(); ?> -->
									<?php $featured_post_count ++;
									endwhile;
								echo '</div><!-- .top-featured-post-wrap -->';
								endif;
						echo '</div><!-- .top-featured-post-main-wrapper -->';
					} ?>
				</div>
			</div><!-- .fron-slider-wrapper -->
<?php
	}

Вот сайт: http://q908121m.beget.tech/