Server side processing Jquery Datatables Sharepoint

I have a >50000 SharePoint Online document library list being rendered using the working code below. The page load time is close to 10-15 seconds.

I tried to implement server side processing to reduce page load times, but it made no difference:

"processing": true, "serverSide": true,

<!DOCTYPE html>    
<html">    
<head>    
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/jquery-3.5.1.js"></script>        
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/jquery.dataTables.min.js"></script>     
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/moment.min.js"></script>     
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/datetime-moment.js"></script>      
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/dataTables.buttons.min.js"></script>       
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/buttons.flash.min.js"></script>            
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/jszip.min.js"></script>        
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/pdfmake.min.js"></script>      
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/vfs_fonts.js"></script>            
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/buttons.html5.min.js"></script>        
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/buttons.print.min.js"></script>        
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/dataTables.select.min.js"></script>    
    <script type="text/javascript" src="<SPO_SITE>/SiteAssets/js/dataTables.searchBuilder.min.js"></script> 
    <link rel="stylesheet" type="text/css" href="<SPO_SITE>/SiteAssets/css/jquery.dataTables.min.css">    
    <link rel="stylesheet" type="text/css" href="<SPO_SITE>/SiteAssets/css/dataTables.jqueryui.min.css">      
    <link rel="stylesheet" type="text/css" href="<SPO_SITE>/SiteAssets/css/buttons.dataTables.min.css">  
    <link rel="stylesheet" type="text/css" href="<SPO_SITE>/SiteAssets/css/select.dataTables.min.css">  
    <link rel="stylesheet" type="text/css" href="<SPO_SITE>/SiteAssets/css/searchBuilder.dataTables.min.css">  

<script>
$(document).ready(function() {loadItems();});    

function loadItems() {    
    var siteUrl = _spPageContextInfo.siteAbsoluteUrl;    
    var oDataUrl = siteUrl + "/_api/web/lists/getbytitle('LIST_NAME')/items?$top=200000&$select=Created,ATA,EncodedAbsUrl";    
    $.ajax({    
        url: oDataUrl,    
        type: "GET",    
        dataType: "json",    
        headers: {    
            "accept": "application/json;odata=verbose"    
        },    
        success: mySuccHandler,    
        error: myErrHandler    
    });    
}    
  
function mySuccHandler(data) {    
    try {    
          
        $('#table_id').DataTable({    
            "pageLength": 100,
            "dom": 'Bfrtip',
            "buttons": [ {extend: 'searchBuilder', config: {columns: [0,1,2,3,4,5,6,7],},}, 'copy', 'csv', 'pdf', {extend: 'print',exportOptions: {columns: [ 0, 1, 2, 3, 4, 5, 6, 7 ]}} ],
            "aaData": data.d.results,
            "aaSorting": [[0, "desc"]],
            "aoColumns": [  
            {    
                "mData": "Created"
            },             
            {    
                "mData": "ATA"    
            },             
            {    
                "mData": "EncodedAbsUrl",
                "mRender": function ( data, type, full )
                {return '<a href="'+data+'" target="_blank">View</a>';}             
            }
            ]    
        });    
    } catch (e) {    
        alert(e.message);    
    }    
}    
    
function myErrHandler(data, errMessage) {    
    alert("Error: " + errMessage);    
}   
</script>

</head>    
<body>    
   <div> 
    <table id="table_id" class="display" cellspacing="0" width="100%">    
        <thead>    
            <tr>    
                <th>Uploaded</th>    
                <th>ATA</th>
                <th></th>           
            </tr>    
        </thead>    
    </table>    
    </div>    
</body>    
</html>