Set featured image with javascript

Hello,

I need your help to acomplish one task. I’m sure I’m missing something but can’t figure out what.

I have an ajax call that send’s an URL (image file) and a file name to PHP to upload it to media gallery. After the upload, it returns the image ID and then I need to insert it into post. This last step is where I need your help. I already confirmed data sent back to ajax call is the ID of the image (open the image in gallery and ID is the same sent to Ajax call).

My PHP function:

function file_upload_auto ()
{
    if (!isset ($_REQUEST['file_up'])) {

        $return_value = 'Something went wrong' ;
        return $return_value ;
    }

    $file = $_REQUEST['file_up'];
    $filename = $_REQUEST['fname'];
    

    // Add Featured Image to Post
    $image_url        = $file; // Define the image URL here
    $image_name       = $filename . ".jpg";
    $upload_dir       = wp_upload_dir(); // Set upload folder
    $image_data       = file_get_contents($image_url); // Get image data
    $unique_file_name = wp_unique_filename( $upload_dir['path'], $image_name ); // Generate unique name
    $filename         = basename( $unique_file_name ); // Create image file name

    // Check folder permission and define file location
    if( wp_mkdir_p( $upload_dir['path'] ) ) {
        $file = $upload_dir['path'] . '/' . $filename;
    } else {
        $file = $upload_dir['basedir'] . '/' . $filename;
    }

    // Create the image  file on the server
    file_put_contents( $file, $image_data );

    // Check image file type
    $wp_filetype = wp_check_filetype( $filename, null );

    // Set attachment data
    $attachment = array(
        'post_mime_type' => $wp_filetype['type'],
        'post_title'     => sanitize_file_name( $filename ),
        'post_content'   => '',        
        'post_status'    => 'inherit'
    );

    // Create the attachment
    $attach_id = wp_insert_attachment( $attachment, $file, $post_id );

    // Include image.php
    require_once(ABSPATH . 'wp-admin/includes/image.php');

    // Define attachment metadata
    $attach_data = wp_generate_attachment_metadata( $attach_id, $file );

    // Assign metadata to attachment
    wp_update_attachment_metadata( $attach_id, $attach_data );

    //$duvida = json_encode($attach_id);
    
    echo $attach_id;
    wp_die();

}

My JS:

function fileuploader(file, filename){
    console.log(file);
    console.log(filename);
    $.ajax({
        type: 'POST',
        dataType: 'json',
        url: '/wp-admin/admin-ajax.php',
        data: {
            action: 'call_file_uploader',
            file_up: file,
            fname: filename
        },
        
        success: function(data) {
            console.log(data);
            wp.media.featuredImage.set( data );
        },
        error: function (jqXHR, exception) {
        var msg = '';
        if (jqXHR.status === 0) {
            msg = 'Not connect.\n Verify Network.';
        } else if (jqXHR.status == 404) {
            msg = 'Requested page not found. [404]';
        } else if (jqXHR.status == 500) {
            msg = 'Internal Server Error [500].';
        } else if (exception === 'parsererror') {
            msg = 'Requested JSON parse failed.';
        } else if (exception === 'timeout') {
            msg = 'Time out error.';
        } else if (exception === 'abort') {
            msg = 'Ajax request aborted.';
        } else {
            msg = 'Uncaught Error.\n' + jqXHR.responseText;
        }
        
    }, 
    });    
}

I thought when using:
wp.media.featuredImage.set( data ); it was supposed to attach the image to the post, but it seems nothing happens. If I open the gallery inside the new post page, the image is right there to be used.

Could someone point me in the right direction please?