Using the original pagination function. See https://stackoverflow.com/q/58709835 for details.

template-test.php

<?php
/* Template Name: Test */
?>
<!-- Add other markup as necessary.. -->
<?php get_header(); ?>
<div class="bg-light">
	<div class="container space-top-3 space-bottom-2">
		<div class="row">
			<?php
			$paged = max( get_query_var( 'paged' ), get_query_var( 'page' ), 1 );
			$args = array(
				'post_type'       => 'post',
				'orderby'         => 'post_date',
				'order'           => 'desc',
				'perm'            => 'readable',
				'show_post_views' => true,
				'posts_per_page'  => 9,
				'paged'           => $paged
			);
			$latestArticles = new WP_Query( $args );

			if ( $latestArticles->have_posts() ) :
				while ( $latestArticles->have_posts() ) : $latestArticles->the_post();
					get_template_part( 'loop-templates/content-search', get_post_format() );
				endwhile;
			?>
		</div>

		<div class="row mt-3">
			<div class="col-auto">
				<?php
					$orig_max_num_pages = $wp_query->max_num_pages; // backup

					// Change it just for the pagination.
					// and $latestArticles is your custom WP_Query instance.
					$wp_query->max_num_pages = $latestArticles->max_num_pages;

					understrap_pagination( [
						'current' => $paged,
					] );

					$wp_query->max_num_pages = $orig_max_num_pages; // restore
				?>
			</div>
		</div>

		<?php wp_reset_postdata(); ?>
		<?php else : ?>
			<!-- do nothing -->
		<?php endif; ?>
	</div>
</div>
<?php get_footer(); ?>