How to display related posts according to Title and Category on a WordPress single page?

Here is my code:

<?php 
$args = array(                          
    'category__in'   => $cat_id, // OK
    'posts_per_page' => 6,
    'post__not_in'   => array( get_the_ID() ),
);
                    
$wpex_query = new WP_Query( $args );
?>

Note: Using category in query is OK. But I also want the Title in the query.