How to Use ACF Fields for WooCommerce Product Photos. See https://cfxdesign.com/how-to-use-acf-fields-for-woocommerce-product-photos

load_existing_product_gallery_into_acf_gallery_field.php

<?php

  function load_existing_product_gallery_into_acf_gallery_field($field) {
    global $post;
    $field['value'] = explode(',', get_post_meta($post->ID, '_product_image_gallery', true));
    return $field;
  }
  add_filter('acf/load_field/name=product_gallery', 'load_existing_product_gallery_into_acf_gallery_field');

load_existing_product_photo_into_acf_image_field.php

<?php

  function load_existing_product_photo_into_acf_image_field($field) {
    global $post;
    $field['value'] = get_post_meta($post->ID, '_thumbnail_id', true);
    return $field;
  }
  add_filter('acf/load_field/name=product_photo', 'load_existing_product_photo_into_acf_image_field');

remove_woocommerce_product_image_meta_boxes.php

<?php

  function remove_woocommerce_product_image_meta_boxes() {
    remove_meta_box('postimagediv', 'product', 'side');
    remove_meta_box('woocommerce-product-images', 'product', 'side');
  }
  add_action('add_meta_boxes', 'remove_woocommerce_product_image_meta_boxes', 40);

use_acf_fields_for_product_photos.php

<?php

  function use_acf_fields_for_product_photos($post_id) {
    if('product' != get_post_type($post_id)) {
      return false;
    }

    $product_photo = get_field('product_photo', $post_id);
    if($product_photo && !empty($product_photo['ID'])) {
      update_post_meta($post_id, '_thumbnail_id', $product_photo['ID']);
    }

    $product_gallery = get_field('product_gallery', $post_id);
    if($product_gallery) {
      $product_gallery_ids_string = implode(',', wp_list_pluck($product_gallery, 'ID'));
      update_post_meta($post_id, '_product_image_gallery', $product_gallery_ids_string);
    }
  }
  add_action('acf/save_post', 'use_acf_fields_for_product_photos', 20);