Get discount information after order

Thank you for your answer. I looked at the samples in the link you sent. However, I couldn’t find what I was looking for.
I hope you understand what I mean. I’m wondering if there is a function that does this. Otherwise unfortunately I’ll have to deal with it myself, work on it and write a new function.

There is a product named A.
Regular Price: $100 dollars
Sale Price: $50

The customer adds the product to the cart and successfully purchases the product.
This is where I start everything. I want to get regular price and sale price “on order”. So, I’m looking for questions like how much did the customer buy this product and bought it at a discount.
Yes, you can have this product-based information:

foreach ($order->get_items() as $item_id => $item ) {
    $regular_price = $product->get_sale_price(); // The product raw sale price

    $sale_price = $product->get_regular_price(); // The product raw regular price
}

But of course this is not true. Because, this price may change later. For example, the discounted price can be removed. That is, only regular price ($100) can be sold. Or a price of more: $110.

This is not a complex development issue. Unfortunately, you are copy-pasting canned answers. Previously, Woocommerce support was not like this.
I’m not asking you to write code. Such a function, usage etc. I’m asking whether there is or not.

I also wrote what you call complex. Maybe it helps someone else. I am sharing it below.
Have a nice day.

/**
* If there is a discounted item, save it in the woocommerce_order_itemmeta table for further use.
* 
* @return void
*/
add_action( 'woocommerce_payment_complete', 'order_check_discounted_price_control' );
function order_check_discounted_price_control( $order_id ){ 
	//create order object
	$order = wc_get_order($order_id); 
	foreach ($order->get_items() as $item_id => $item ) { 
		$product = $item->get_product();
	//Check if the item is discounted
	if($product->get_sale_price() != $product->get_regular_price()){
		
		wc_add_order_item_meta($item_id,'_discounted_item', $product->get_regular_price());
	}
	
}