Export custom meta data before line item columns in CSV with Order / Coupon / Subscription Import  Export Plugin for WooCommerce (https://www.webtoffee.com/product/order-import-export-plugin-for-woocommerce/)

functions.php

<?php // do not copy this line
add_filter('hf_alter_csv_header', 'hf_csv_order_add_more_columns', 10, 1);

function hf_csv_order_add_more_columns($csv_columns)
{
    $new_csv_columns = array();
    $lineitem_csv_columns = array();
    $temp_order_metadata = array('RDI','LDI');   //Give the custom field required to export
    foreach ($csv_columns as $data_key => $data_value) {
        if(strstr($data_key, 'line_item_')){
           $lineitem_csv_columns[$data_key] = $data_value;
           unset($csv_columns[$data_key]);
        }
        
    }
    $new_csv_columns = array_merge($csv_columns,$temp_order_metadata,$lineitem_csv_columns);
    return $new_csv_columns;
}

add_filter('hf_alter_csv_order_data', 'wt_alter_csv_order_data', 10, 1);

function wt_alter_csv_order_data($order_data) {
    $new_csv_columns = array();
    $lineitem_csv_columns = array();
    $temp_order_metadata = array('RDI', 'LDI');   //Give the custom field required to export
    foreach ($order_data as $d_key => $d_value) {
        if (strstr($d_key, 'line_item_')) {
            $lineitem_csv_columns[$d_key] = $d_value;
            unset($order_data[$d_key]);
        }
    }

    foreach ($temp_order_metadata as $key => $value) {
        $order_data[$value] = get_post_meta($order_data['order_id'], $value, true);
    }
    $new_csv_columns = array_merge($order_data, $lineitem_csv_columns);
    return $new_csv_columns;
}