Any way to bypass fetch() character limit? [closed]

So, I was making a HTML loader that uses HTML from raw GitHub URLS. Smaller HTMLs loaded but when I tried to load larger HTMLS they were incomplete. Every time I loaded a large HTML they cut off at the same time. Is this a character limit? Or is this a problem with my code?

I don’t really know how to fix this which is why I’m asking. Code down below:

<html>
    <head>
        <title>f1re</title>
    </head>
    <body>
        <div class="topbar">
            <button class="bl small" onclick="reload()">
                ↻
            </button>
            <button class="small" onclick="info()">?</button>
            <input type="text" id="URL" placeholder="Enter GIT URL">
            <button class="br big" onclick="loadFunc()">
                Go to URL
            </button>
        </div>
        <iframe id="frame"></iframe>
    </body>
    <script>
        let proxy = "";
        let curr = 'about:blank';
        async function loadFunc(){
            let link = document.querySelector("#URL").value;
            let data = await fetch(proxy.toString()+link.toString());
            let doc = await data.text();
            curr = link;
            document.querySelector("#frame").src = "data:text/html;charset=utf-8,"+doc.toString();
        }
        async function reload(){
            let link = curr;
            let data = await fetch(proxy.toString()+link.toString());
            let doc = await data.text();
            curr = link;
            document.querySelector("#frame").src = "data:text/html;charset=utf-8,"+doc.toString();
        }
        function info(){
            alert('f1re only works for GIT URLS.');
            if(prompt('View GIT URL list? [Y]es / [N]o').toString() === 'Y'){
                alert('Viewing GIT URLS... Click OK to open next page.');
                alert('https://raw.githubusercontent.com/ThisAintComputin/GitSite/refs/heads/main/Main.html');
                alert('NOTE: You can make your own GIT sites. (it is very complicated for beginners though)');
            };
        }
    </script>
    <style>
        body{
            margin: 0px;
        }
        .topbar{
            display: flex;
            position: fixed;
            top: 0%;
            left: 0%;
            right: 0%;
        }
        #URL{
            width: 85%;
            text-align: center;
        }
        .big{
            width: 10%;
        }
        .small{
            width: 5%;
        }
        button{
            background-color: black;
            color: red;
        }
        input{
            background-color: black;
            color: red;
        }
        .bl{
            border-bottom-left-radius: 10px;
        }
        .br{
            border-bottom-right-radius: 10px;
        }
        #frame{
            width: 100%;
            height: 90%;
            position: fixed;
            top: 3%;
            border: none;
        }
    </style>
</html>