Wordpress: Search in ACF fields loop

gistfile1.txt

           <form method="GET" action="/url-of-your-current-page/">
              <input type="text" name="search" class="search-string" placeholder="">
              <a class="search-clear"><i class="fa fa-times-circle" aria-hidden="true"></i>
              </a>
              <button type="submit">Search</button>
          </form>
          
                 //search block js
                 function getUrlParameter(name) {
                   name = name.replace(/[\[]/, '\\[').replace(/[\]]/, '\\]');
                   var regex = new RegExp('[\\?&]' + name + '=([^&#]*)');
                   var results = regex.exec(location.search);
                   return results === null ? '' : decodeURIComponent(results[1].replace(/\+/g, ' '));
                 }
                 jQuery('input[name="search"]').attr('placeholder', getUrlParameter('search'));
                 jQuery('.search-clear').click(function(e){
                   e.preventDefault();
                   window.location.href = window.location.href.split('?')[0];
                 })
          
           //php template
           <?php
           $search_str = get_query_var('search') ? get_query_var('search') : '';

            // filter for searching in post-titles only
            function title_filter($where, &$wp_query){
            global $wpdb;
            if($search_term = $wp_query->get( 'title_filter' )){
                    $search_term = $wpdb->esc_like($search_term); //instead of esc_sql()
                    $search_term = ' \'%' . $search_term . '%\'';
                    $title_filter_relation = (strtoupper($wp_query->get( 'title_filter_relation'))=='OR' ? 'OR' : 'AND');
                    $where .= ' '.$title_filter_relation.' ' . $wpdb->posts . '.post_title LIKE '.$search_term.' AND post_type = "customers"';
                    }
                    return $where;
                    };

                    add_filter('posts_where','title_filter',10,2);

                    // args for searching in ACF and post-title (using title_filter)
                    $args = array(
                        'post_type' => 'customers',
                        'posts_per_page' => -1,
                        'orderby' => 'menu_order title',
                        'order' => 'ASC',
                        'post_status' => 'publish',
                        'post__not_in' => array(665356),
                        'title_filter' => $search_str,
                        'title_filter_relation' => 'OR',
                        'meta_query'    => array(
                            array(
                            'key' => 'case_study_text',
                            'value' => $search_str,
                            'compare' => 'LIKE'
                            ),
                            'relation' => 'OR'
                        )
                    );

                    $the_query = new WP_Query($args);

                    if ($the_query->have_posts()):

                    while ($the_query->have_posts()) :
                    $the_query->the_post();
                    $post_id = get_the_ID();
                    $the_post = get_post($post_id);
                    ?>
                    
                    ...
                    
                    <?php endwhile; endif;?>
                    <?php wp_reset_query(); ?>