Using Advanced Custom Fields Relationship Field to select a taxonomy term

This is based on the assumption that you have a custom field called “show_on_tax” for the custom taxonomy “Directory Entry Type”, which appears when editing a small banner (See image below). This allows you to select which custom tax terms you want the banners to appear on. This should get you sorted but drop a comment if not.

<?php 
// taxonomy-directory_entry_type.php template file

// Get currently viewed term id
$term_id = get_queried_object()->term_id;

// Get all banners with show_on_tax custom field matching to $term_id
$args = array(
    'post_type' => 'small-banner',
    'posts_per_page' => -1,
    'meta_query' => array(
        array(
            'key' => 'show_on_tax',
            'value' => $term_id,
            'compare' => 'LIKE'
        )
    )
);

// Create custom banner query
$banner_query = new WP_Query( $args );

// Check if anything is found and do the custom loop
if ( $banner_query->have_posts() ) : ?>

    <div class="my-slider" style="width: 380px;">
        <ul>

        <?php while ( $banner_query->have_posts() ) : $banner_query->the_post(); ?>

            <?php $photo = get_field( 'small_banner_image', get_the_ID() ); ?>

            <li>
                <a href="https://wordpress.stackexchange.com/questions/253773/<?php the_field("small_banner_image' ); ?>">
                    <img src="<?php echo $photo['url']; ?>" alt="<?php echo $photo['alt']; ?>">
                </a>
            </li>

        <?php endwhile; ?>

        </ul>
    </div>

<?php
endif;

wp_reset_postdata();
?>

Custom field settings