How to replace the choice of the maximum number of goods in Bitrix?

Question

PHP

Hello, Aspro-Maximum Solution, such a question.
The bottom line is that there is one database in which goods go by the piece (I can’t change them), let’s say 5000 goods and there is a property how many pieces are in 1 package, let’s say 50 pieces
and I need to limit to a maximum of 100 goods so that they can buy this particular product, and t .to. the quantity hits 5000 at once, then people can issue 5000 packages, but in fact there are only 50 pieces of packages

On the detailed page of the product, I decided to do this))) works

<? $tovar1 = $arResult["PROPERTIES"]["KOMPLEKTATSIYA_PERVICHNAYA_UPAKOVKA"]["VALUE"];
   $str = preg_replace("/[^0-9]/", '', $tovar1);
   $delenie = $arResult['CATALOG_QUANTITY'];
   $finish = (int)($delenie / $str);
 
?>

<script>
    var username = "<?php echo $finish ?>";
$('.plus').attr('data-max', '<?php echo $finish ?>');
</script>

How to set a different value for the available quantity of an item in the cart? this maneuver does not work anymore sale.basket.basket

<td class="basket-items-list-item-amount">
            <div class="basket-item-block-amount{{#NOT_AVAILABLE}} disabled{{/NOT_AVAILABLE}}"
               data-entity="basket-item-quantity-block">
               <span class="basket-item-amount-btn-minus" data-entity="basket-item-quantity-minus"></span>
               <div class="basket-item-amount-filed-block">
                  <input style="display:none" type="text" class="basket-item-amount-filed" value="{{QUANTITY}}"
                     {{#NOT_AVAILABLE}} disabled="disabled"{{/NOT_AVAILABLE}}
                     data-value="{{QUANTITY}}" data-entity="basket-item-quantity-field"
                     id="basket-item-quantity-{{ID}}">

               </div>
   <span class="basket-item-amount-btn-plus" data-entity="basket-item-quantity-plus"></span> 

               {{#SHOW_LOADING}}
                  <div class="basket-items-list-item-overlay"></div>
               {{/SHOW_LOADING}}
            </div>
         </td>

I decided to make measurements through the coefficient unit, put the handler in init.php, but for some reason it doesn’t fly

<?

  AddEventHandler("iblock", "OnAfterIBlockElementUpdate", "OnAfterIBlockElementUpdateHandler");
  function OnAfterIBlockElementUpdateHandler(&$arFields)
{
Cmodule::IncludeModule('iblock');
Cmodule::IncludeModule('catalog');
$iblockId = 18;
$updateElements = CIBlockElement::GetList(
   Array("ID" => "ASC"),
   Array("IBLOCK_ID" => $iblockId),
   false,
   false,
   Array(
       'ID',
       'KOMPLEKTATSIYA_PERVICHNAYA_UPAKOVKA'
   )
);
while ($arFields = $updateElements->GetNext()) {
 
   $coeff = $arFields['KOMPLEKTATSIYA_PERVICHNAYA_UPAKOVKA'];
   $newcoef = preg_replace("/[^0-9]/", '', $coeff);

   
   $curElementRatio = CCatalogMeasureRatio::getList(
         Array(),
         array('IBLOCK_ID' => $iblockId, 'PRODUCT_ID' => $arFields['ID']),
         false, false);
         while ($arRatio = $curElementRatio->GetNext()) {
              $ratioId = $arRatio['ID'];
         }

   CCatalogMeasureRatio::update($ratioId, Array(
          'PRODUCT_ID' => $arFields['ID'],
          'RATIO' => $newcoef)
    );
}
}
?>

Gives this error

[TypeError] 
Argument 1 passed to Bitrix\Catalog\Config\State::handlerAfterIblockElementUpdate() must be of the type array, bool given, called in /var/www/html/bitrix/modules/main/classes/general/module.php on line 480 (0)
/var/www/html/bitrix/modules/catalog/lib/config/state.php:243
#0: Bitrix\Catalog\Config\State::handlerAfterIblockElementUpdate
  /var/www/html/bitrix/modules/main/classes/general/module.php:480
#1: ExecuteModuleEventEx
  /var/www/html/bitrix/modules/iblock/classes/mysql/iblockelement.php:1757
#2: CIBlockElement->Update
  /var/www/html/bitrix/modules/iblock/admin/iblock_element_edit.php:1047
#3: require(string)
  /var/www/html/bitrix/admin/iblock_element_edit.php:1