I have a custom page template that includes a basic query after the main content. like this:

$myPosts = new WP_Query(
  array(
    'post_type' => array('post', 'contentTypeA', 'contentTypeB' ),
    'posts_per_page' => 10,
    'order' => 'DESC',
  )
);

if ( $myPosts->have_posts() ) :
  while ( $myPosts->have_posts() ) : $myPosts->the_post();
    get_template_part( 'template-parts/content', get_post_type() );
  endwhile;
endif;
wp_reset_postdata();

My problem is that the results think that they are single pages. The template part linked by get_template_part() has a condition that if is_singular() is true, among many other things, render the title as <h1>, otherwise render as <h2>.

In my WP_Query feed, all the results are using <h1> for titles because is_singular() is registering as true for the posts.

So, my question is: is there an argument I can pass to my WP_Query to force the results to think that is_singular() is false? In other words, to make this output like a standard archive page.

I have discovered that if I use if ( is_singular() && in_the_loop() ) : it sort of does the trick, but I am hoping there is a much simpler solution than adding that to the dozens of template partials I have that rely on is_singular().