Problem with foreach loop

I’m customizing my theme’s category template to display the current category’s child categories instead of the posts from that category.

The category template links to another template file (content-grid.php) which generates the dynamic post/category content.

The only way I can get it to work is by including all the code on the category template.

This is how the original category template links to content-grid.php (I’m only showing the relevant code):

echo '<div class="row">';
while ( have_posts() ) : the_post();
$count++;
get_template_part( 'template-parts/content-grid' );
if ( $count % 2 == 0 ) {
echo '</div>';

In my customized template I’ve changed the standard loop to a “foreach” loop and link to the same file like this:

echo '<div class="row">';
foreach ( $child_categories as $child ){
$count++;
get_template_part( 'template-parts/content-grid' );
if ( $count % 2 == 0 ) {
echo '</div>';