Snippet that detects if a given ACF Page URL is an attachment page, detects the ID of that attachment page, and returns the URL for the actual attachment.

attachment-detector.php

<?php 
    $ctaLink = get_field('static_hero_cta_button_link');
    if (false !== strpos($ctaLink,'attachment_id')) {
        $url = $ctaLink;
        $url_parsed = parse_url($url);
        parse_str($url_parsed['query'], $url_parts);
        $attachmentID = $url_parts['attachment_id']; // attachment ID
        $attachmentSrc = wp_get_attachment_url( $attachmentID ); // returns an array   
        $ctaLink = $attachmentSrc;
     }
?>