How to pre-set WordPress settings for specific posts?

After scouring on the net and bouncing around, I figured out how to fix my problem.

1. Install ACF and create your own post types.

2. In Functions.php, add the following codes to default category for that post type.

   function add_pastorheart_category_automatically($post_ID) {
       global $wpdb;
       if(!wp_is_post_revision($post_ID)) {
       $pastorheartcat = array (15);
       wp_set_object_terms( $post_ID, $pastorheartcat, 'category');
   
       }
   }
   add_action('publish_pastors-heart', 'add_pastorheart_category_automatically');
   

3. Also add this function to include the post type in the category.

   function namespace_add_custom_types( $query ) {
     if( is_category() || is_tag() && empty( $query->query_vars['suppress_filters'] ) ) {
       $query->set( 'post_type', array(
        'post', 'nav_menu_item', 'pastors-heart'
           ));
         return $query;
       }
   }
   add_filter( 'pre_get_posts', 'namespace_add_custom_types' );
   

4. For default thumbnail image, I put this code in the content-excerpt.php. Instead of checking for post types, I check for category.

It might not be the most elegant way of doing it. But it works for me.