Output Post with ACF Fields into other Post

To not duplicate code you could make a file in your theme/child-theme for the html of the post which you intend to embed, let’s say x_cpt_render_html.php:

function get_x_cpt_html(){ ?>
<div class="x-cpt">
<h2> <?php the_title(); ?> </h2>
<div class="content"> <?php the_content(); ?></div>
<div class="custom"> <?php the_field('custom'); ?> </div>
</div><?php
}

Then you could embed this file in the single.php or wherever it’s needed anyway for display for that particular custom post type:

get_template_part('x_cpt_render_html');
while ( have_posts() ) : the_post();
get_x_cpt_html();
endwhile;

Somewhat similar where you want to embed it:

$loop = new WP_Query( array( 'post_type' => 'that_post_type',
        'posts_per_page' => -1,);
get_template_part('x_cpt_render_html');
while ( $loop->have_posts() ) : $loop->the_post();
get_x_cpt_html();
endwhile;
wp_reset_postdata();