Get subtotals excluding tax for each Tax Rate in Cart summary - Magento 2

Hay yesss, I found a solution so I'm answering to myself, maybe this will be usefull to someone else with the same needing. N.B. Sorry if the code is not too much pretty, since I'm not a developer... any suggestion or contribution in this way will be appreciated, I'll take care of keeping this post updated.

The files edited are: vendor/magento/module_tax/view/frontend/web/js/view/checkout/cart/totals/tax.js vendor/magento/module_tax/view/frontend/web/template/checkout/cart/totals/tax.html

The above files are copied in my child theme under "//Magento_tax/web/" folder, and then modified:

• in tax.js added this function at the bottom

   /** 
    * return subtotalByRate
    */
   getSubTaxTotal: function (parent, percentage) {
       // get current rate
       var currentRate = percentage;
       // declare subtotalByRate var
       var subtotalByRate = 0;
       // target items in chart measuring array
       var itemsSegment = this.totals()["items"];
       // get qty of items in chart
       var ItemsQty = Object.keys(itemsSegment).length;
       // declare rates var
       var rates = 0;
       rates = parent.rates;
       _.each(rates, function (rate) {
           // extract total for tax rate function
           // start loop for chart items
           for(var i=0; i < ItemsQty ; i++) {
               // check if the item have the same taxRate,  then add rowPrice tax escluded
               if (itemsSegment[i].tax_percent == currentRate) {
                   subtotalByRate = subtotalByRate + itemsSegment[i].base_row_total;
               }
           }
       });
       // the loop is twice (don't know why..) so divide by 2
       subtotalByRate = subtotalByRate/2;
       return this.getFormattedPrice(subtotalByRate);
   }
  

• in tax.html added this HTML right after "ko forEach: rates" statement

    <tr class="tax-subtotal-summary">
        <th class="mark" scope="row" colspan="1" data-bind="text: 'Subtotale soggetto a ' + title + ' (' + percent + '%)'"></th>
        <td class="amount" rowspan="1">
        <span class="price"
                  data-bind="text: $parents[1].getSubTaxTotal($parents[0], percent), attr: {'data-th': title, 'rowspan': $parents[0].rates.length }"></span>
       </td>
  

This is the result on my cart