Showing json data from javascript fetch request from browser to different url

I wrote this issue late at night after banging away with frustration for 2 days on it, so let me add a couple things and fix a couple typos.

I am loading a script that would be loaded in via google tag manager with the following url: example.org/somescript.js so that when the user visits example.com/something/?userid=ABC the script example.org/somescript.js loads on to the page via the google tag manager

The script goes around and makes some color choices to the DOM.

All good.

Inside the script, it makes a fetch request based on the user ID to a remote url: example.net

//scriptblock_1

const getstuff = fetch("https://example.net/users/abc")
        .then((response) => response.text())
        .then((data) => {
            return data;
        }
    );


const dostuff = () => {
    getstuff.then((a) => {
         console.log(a);  // will result in test
         console.log(JSON.parse(a).custom_css_final);    // will result in undefined
         var css2 = document.createElement('style');
         css.id = 'newcss'
         css.setAttribute('type', 'text/css');
         document.getElementsByTagName('head')[0].appendChild(css);

         setTimeout(function() {
            if (css.styleSheet) {
                css.styleSheet.cssText = JSON.parse(a).custom_css_final;
            } else {
                css.appendChild( document.createTextNode(JSON.parse(a).custom_css_final) );
            }
         }, 300)
     })
}

dostuff();

https://example.net/users/abc will return a payload like this:

{"status": false, "cool":"cool", "custom_css_final":".something { color: #00FF00; }"}

I am attempting to use safe simple cors headers, so my response from example.net returns stringified data like this. The server side code uses this to make the payload response:

var data = {
    "status": false,
    "cool":"cool",
    "custom_css_final":".something { color: #00FF00; }"
}
var json = JSON.stringify(data)
const init_no_authresponse = { headers: {
 "content-type": "text/plain", 
 "Access-Control-Allow-Origin": "*",
 "Cache-Control": "no-store, max-age=0"
}, status: 200 }

return new Response(json, init_no_authresponse)

If I paste this code from scriptblock_1 into the browser console it runs fine, if I load this from the website load, it will not show the parsed data: ie console.log(a).custom_css_final instead will show undefined while just console.log(a) will show the total response.

I believe this is a CORS issue, can anybody spot the issue and how to resolve it? Is it my header data I am returning, is it the way I am fetching? Thanks.

Anybody understand how I am treat his promise or CORS issue improperly? Appreciate it!