Display a post Specific URL only on listings with value

functions.php

function custom_listify_single_job_listing_actions_after() {
    global $post;
    
    $url = get_post_meta( $post->ID, 'custom_URL', true );
    if (!$url) {
      return;
    }
    echo '<a href="' . esc_url( $url ) . '" class="button">My Button</a>';
}
add_filter( 'listify_single_job_listing_actions_after', 'custom_listify_single_job_listing_actions_after' );