$useConfigManageStock = '0';
$manageStock = '0';

$collection->addAttributeToSelect('*')->load();

$customStock = ['use_config_manage_stock' => $useConfigManageStock, 'manage_stock' => $manageStock];

foreach ($collection as $product) {
            $product->setStockData($customStock);
            $product->save();
        }