JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<div id='product-component-1635439141053'></div>
<script type="text/javascript">
/*<![CDATA[*/
(function () {
  var scriptURL = 'https://sdks.shopifycdn.com/buy-button/latest/buy-button-storefront.min.js';
  if (window.ShopifyBuy) {
    if (window.ShopifyBuy.UI) {
      ShopifyBuyInit();
    } else {
      loadScript();
    }
  } else {
    loadScript();
  }
  function loadScript() {
    var script = document.createElement('script');
    script.async = true;
    script.src = scriptURL;
    (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(script);
    script.onload = ShopifyBuyInit;
  }
  function ShopifyBuyInit() {
    var client = ShopifyBuy.buildClient({
      domain: 'gorilla-fitness-equipment.myshopify.com',
      storefrontAccessToken: '2fae533b5bb0c29a895e3394bc8987cf',
    });
    ShopifyBuy.UI.onReady(client).then(function (ui) {
      ui.createComponent('product', {
        id: '4956146244',
        node: document.getElementById('product-component-1635439141053'),
        moneyFormat: '%24%7B%7Bamount%7D%7D',
        options: {
  "product": {
    "styles": {
      "product": {
        "@media (min-width: 601px)": {
          "max-width": "calc(25% - 20px)",
          "margin-left": "20px",
          "margin-bottom": "50px"
        }
      },
      "button": {
        "font-family": "Roboto, sans-serif",
        "font-weight": "bold",
        "font-size": "16px",
        "padding-top": "16px",
        "padding-bottom": "16px",
        ":hover": {
          "background-color": "#4aa04d"
        },
        "background-color": "#52b256",
        ":focus": {
          "background-color": "#4aa04d"
        },
        "border-radius": "0px",
        "padding-left": "100px",
        "padding-right": "100px"
      },
      "quantityInput": {
        "font-size": "16px",
        "padding-top": "16px",
        "padding-bottom":...

JavaScript

//when page loads 
setTimeout(function() {           
      var iframePreLoad = $("#product-component-1635439141053").children().contents();
      iframePreLoad.find(".shopify-buy__option-select__select").ready(function(){
        iframePreLoad.find('select[name=Color] option:nth-child(1)').html('Black');  
        iframePreLoad.find('select[name=Color] option:nth-child(2)').html('Green');
      }); 

//When selection is made
       iframePreLoad.find('select').on('change', function() {
       	setTimeout(function() {
        	iframePreLoad.find('select[name=Color] option:nth-child(1)').html('Black');  
          iframePreLoad.find('select[name=Color] option:nth-child(2)').html('Green');
        },100)
       	 

      	console.log('selection changed');
       });
}, 3000);