Unable to display template from database to grapesjs

Able to fetch my remote HTML file using load URL and getting status ok, how can I load this fetched HTML AND CSS into editor? currently I'm getting blank screen inside editor.

What I tried so far:

storageManager: {
        id: 'gjs-',  
        type: 'remote',
        autosave: false,
        autoload: true,
        setStepsBeforeSave: 1,
        contentTypeJson: true,
        storeComponents: true,
        storeStyles: true,
        storeHtml: true,
        storeCss: true,
        urlStore: '../inc/page/edit_builder.php?id=<?php //echo $pid; ?>',
        urlLoad: '../inc/page/fetch_builder.php?id=<?php //echo $pid; ?>',

        json_encode:{
        'gjs-components': "",
        'gjs-css': [],
        'gjs-html': [],
        'gjs-style': []
        }
      },

From the server

$id = $_GET['id'];
$result = mysqli_query($mysqli, "SELECT * FROM mp_pages WHERE page_id='$id'");
$response= array();
while($row = mysqli_fetch_array($result))

{
                 array_push($response, array(
                "gjs-components"=>$row['gjs-component'], 
                "gjs-css"=>$row['css'], 
                "gjs-html"=>$row['page_desc'], 
                "gjs-style"=>$row['gjs-styles'],    
                
                
               ));

}
echo json_encode($response);

mysqli_close($mysqli);

How can I pass the JSON into grapesjs to make it render the HTML and CSS?