Add Custom field to Product Page update by Script

Hallo All

I Need to add a Custom Field to my ProductPage witch shows me the storage location.
The Script Shows like following:

let productQuantityNum = 200;  //initialize product quantity variable
let soldOutText = "Ab Externem Lager" //initialize variable to display "sold out" text when inventory is 0

$w.onReady(function () {
 //TODO: write your page related code here...
 
  $w('#productPage1').getProduct()  //get current product
  .then( (product) => {
    productQuantityNum = product.quantityInStock;  //get quantity in stock for current product

 if (productQuantityNum > 0) {                 //if it's greater than 0, Display number remaining
 let productQuantityString = productQuantityNum.toString();
      $w("#text47").text = productQuantityString + " remaining";
 
    } else {
      $w("#text47").text = soldOutText;  //display sold out text
    }
  if (productQuantityNum > 999) {                 //if it's greater than 0, Display number remaining
 let productQuantityString = productQuantityNum.toString();
      $w("#text47").text = "Ab externem Lager";
 
    } else {
     
    }
  } )
  .catch( (error) => {
    console.log(error);
  } );
 });

My primary issue is that the code fails to update the textbox when a product with a combobox (e.g., size options) is selected and the selected value is changed.

My second issue is that I want to position my text field below the ‘Add to Cart’ button. However, this doesn’t work consistently across different monitor resolutions because I cannot directly bind the text field element to the ‘Add to Cart’ button. Can someone help me?
Regards, Roger.