Download a Blob in PNG Format

First of all, I hope you had a good Christmas holiday!

I specify that I am a beginner in JS, hence my possible eccentric attempts to try to download my Blob in PNG.

My problem is to export all the graphic content of a DIV in pdf or image format by clicking on a button(the class name of the div is always the same)

After some research I understood that I had to convert the div to canva to be able to download it.
I tried to adapt the code from this post:
How to take screenshot of a div with JavaScript?

But when I click on the button nothing happens despite my various modifications and tests …

Here is a preview of my code :

<html lang="fr">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Export Visualisation QS</title>
</head>
<body>
    <div class="qvt-sheet-container">
        <h1>EXPORT PNG</h1> 
        <img src="Logo-Qlik.png">
    </div>
    <a id="link"><button id="btn-export-qs">Export PNG</button></a>
</body>

<script language="JavaScript" type="text/javascript" src="jquery-3.6.0.min.js">
var a = document.getElementById("link");
function export_feuille() {
    $("#btn-export-qs").click(function() {
        html2canvas($(".qvt-sheet-container"), {
            onrendered: function(canvas) {
                //theCanvas = canvas;
                canvas.toBlob(function(blob) {
                    //saveAs(blob, "Dashboard.png");
                    url = window.URL.createObjectURL(blob);
                    a.href = url;
                    a.download = "export_qs.png";
                    a.click();
                    window.URL.revokeObjectURL(url);
                });
            }
        });
    });
};

document.getElementById("btn-export-qs").addEventListener ("click", export_feuille, false);

</script>
</html>

If anyone could educate me on what is wrong or point me in a direction I would be very grateful 🙂