Magento 2: load disabled category childrens

Question

I need to get all category children of a specific category but disabled categories too.

I have this category tree:

+ Root (ID: 2) // enabled
| + Main 1 (ID: 3) // enabled
| | + Sub 1 (ID: 4) // enabled
| + Main 2 (ID: 5) // enabled
| | + Sub 2 (ID: 6) // enabled
| + Main 3 (ID: 7) // disabled

I need to get all childrens of category with ID 2 [Main1(3),Main2(5),Main3(7)].

I tried with:

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$parentCategoryId = 2;
$parentCategory = $objectManager->get('Magento\Catalog\Model\Category')->load($parentCategoryId);

/*
Also tried with:
$parentCategory = $objectManager->get('Magento\Catalog\Model\Category')->getCollection()
    ->addIdFilter($parentCategoryId)
    ->addAttributeToFilter('is_active', false/0/null/2) // always return an empty array...
    ->getFirstItem();
*/

$parentCategory->getChildren(); // return [3,5]

$cats = [];
foreach($parentCategory->getChildrenCategories() as $cat)
    $cats[] = $cat->getId();

print_r($cats); // return [3,5]

Answer 1

Please try below collection.

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$parentCategoryId = 2;
$parentCategory = $objectManager->get('Magento\Catalog\Model\Category')->load($parentCategoryId);


    $collection =$objectManager->create("\Magento\Catalog\Model\CategoryFactory")->create()->getCollection()->addAttributeToSelect('*')
                      ->setOrder('position', 'ASC')
              ->addFieldToFilter('is_active',array("in"=>array('0', '1')))
                     ->addAttributeToFilter('parent_id',['eq'=>$parentCategoryId]);

        print_r($collection->getData());

I Hope It's Will Helpful.