Magento2 Product – How to Get Image and URL

I think there is no direct method to exclude the configurables, since the logic in Magento is that the configurable is the "main" product where the price is at. The associated simple product might have a wrong price configured. In any case, if you want to still get these items and not the configurables, your best bet is to use the getAllItems() method and then afterwards kick out the configurables:

 $event = $observer->getEvent();
 $order = $event->getOrder();
 $items = $order->getQuote()->getAllItems();
 $itemsExcludingConfigurables = array();
 foreach ($items as $item) {
    if ($item->getTypeId() != 'configurable') {
       $itemsExcludingConfigurables[] = $item;
    }
 }

Please use this even checkout_cart_product_add_after, and also I suggest you that

ObserverInterface has only one method which is execute, so write your code in this method.

And do not use parent Item because while you are adding to cart any item then price depend upon child item so the best way is to use directly that item object that you are getting. So best practice is to use that item itself.

And also return $this object at the end of your code inside execute method.

For eg: namespace Navin\Testcart\Observer;

use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\App\RequestInterface;

class CustomPrice implements ObserverInterface
{
    public function execute(\Magento\Framework\Event\Observer $observer) {

        $item=$observer->getEvent()->getData('quote_item');
        $product=$observer->getEvent()->getData('product');
        // here i am using item's product final price
        $price = $item->getProduct()->getFinalPrice()+10; // 10 is custom price. It will increase in product price.
        // Set the custom price
        $item->setCustomPrice($price);
        $item->setOriginalCustomPrice($price);
        // Enable super mode on the product.
        $item->getProduct()->setIsSuperMode(true);
        return $this;
    }

}

Hope this will help you. :)