Hello @gkhadra,
Unfortunately, extra fields are only retrieved on change, so you can't get them with your code.
You can get item values using pnpjs. Please see the example with filtering below and also have a look at this article.
pnp.sp.web.lists.getByTitle("ListName").items.filter("ID eq '2'").get().then(function(items) {
console.log(items[0].Title);
});