Обновление через коллекцию

bitrix mass update

\Bitrix\Main\Loader::includeModule('iblock');

$iblock = \Bitrix\Iblock\Iblock::wakeUp(3);
$class = $iblock->getEntityDataClass();
$arResult = [];

$elements = $class::getList([
    'select' => ['ID', 'IBLOCK_ID', 'XML_ID', 'ARTICLE'],
    //'limit' => 5000,
    'order' => ['ID' => 'ASC']
])->fetchCollection();

foreach($elements as $element){
    $article = $element->getArticle()->getValue();
    
    if ($article != $element->getXmlId()){
        $arResult[$element->getId()] = $article;
        $element->setXmlId($article);
    }
}

$res = $elements->save(true);

if(!$res->isSuccess()){
    $errors = $res->getErrorMessages();
    print_r($errors);
}