Breaking loop then restarting

I’ve got a custom post type called “Projects” displayed in a grid on my homepage. I’d like to insert three different text blocks within this grid: one before the loop starts, one after the 3rd post, one after the 6th post.

The content for these blocks are served up via an ACF field: ‘intro_text_1’, ‘intro_text_2’, and ‘intro_text_3’.

I got the text block before the loop to work, but I have no idea how to insert the other two.

I’ve read that adding a counter could be helpful here, but I’m really not sure how to correctly implement it.

I’m currently developing locally, so I don’t have a URL to share.

Here is the code I’m using:

<div class="projects-list" id="projects">
	<div class="project-item"><?php the_field('intro_text_1'); ?></div>
  <?php
$args = array( 'post_type' => 'project', 'posts_per_page' => 60 );
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();
?>
<div class="project-item"><a href="<?php the_permalink(); ?>">
   <?php the_post_thumbnail( 'homepage-thumb' ); ?>

   <div class="overlay"><div class="caption">
                        <h2><?php the_title(); ?></h2>
                        <?php
                            $terms = get_the_terms($post->ID, 'work_type');
                            if ($terms) {
                                $terms = array_map(
                                    function($obj) {
                                        return $obj->name;
                                    },
                                    $terms
                                );
                                echo '<div class="project-work-type">(' . implode(', ', $terms) . ')</div>';
                            }
                        ?>
                    </div>
  </div></div>
  </a>
 <?php endwhile;?>

	</div>

I’ve tried various ways of including a counter, but none have worked, likely because I’m not sure where to correctly place them.

Any help would be much appreciated!