Iam sharing my custom js code that iam injecting in my squarespace website but facing an error in report of google page speed insights (error exists only when i add the custom code, otherwise no error).

[This is screenshot of report where the error is comming]
(https://i.sstatic.net/jyZYNRWF.png)

<script>
    if (!sessionStorage.getItem('initialScriptExecuted')) {
        var preloader = document.createElement("div");
        preloader.textContent = "Please wait....";
        preloader.id = "preloader";
        preloader.style.cssText = "position:fixed;top:0;left:0;width:100%;height:100%;background-color:#fff;z-index:10000;display:flex;font-size:14px;justify-content:center;align-items:center";
        document.documentElement.appendChild(preloader);
        sessionStorage.setItem('initialScriptExecuted', 'true');
        setTimeout(function() {
            location.reload(true);
        }, 4000);
    } else {
        var preloader = document.getElementById('preloader');
        if (preloader) {
            preloader.remove();
        }
    }
</script>

I have tried to add the charset tag dynamicall using this script before and after the main script causing the error but still error does not resolve.

<script>
    // Check if the charset meta tag is already present
    var charsetMeta = document.querySelector('meta[charset]');
    
    // If not present, dynamically create and insert it as the first element in the head
    if (!charsetMeta) {
        var newCharsetMeta = document.createElement('meta');
        newCharsetMeta.setAttribute('charset', 'UTF-8');
        document.head.insertBefore(newCharsetMeta, document.head.firstChild);
    }
</script>