Initial

Plugin/Order/View/Items/Renderer/DefaultRenderer.php

@@ -0,0 +1,102 @@
+<?php
+namespace Shopkeeper\OrderItemsCustom\Plugin\Order\View\Items\Renderer;
+
+use Magento\Catalog\Api\ProductRepositoryInterface;
+use Magento\Framework\Exception\NoSuchEntityException;
+
+class DefaultRenderer
+{
+    protected $productRepository;
+
+    public function __construct(
+        ProductRepositoryInterface $productRepository
+    ) {
+        $this->productRepository = $productRepository;
+    }
+
+    /**
+     * Modify columns to remove tax columns and add cost column
+     *
+     * @param \Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer $subject
+     * @param array $result
+     * @return array
+     */
+    public function afterGetColumns($subject, $result)
+    {
+        // Remove tax columns
+        unset($result['tax-amount']);
+        unset($result['tax-percent']);
+
+        // Add cost column after price
+        $newColumns = [];
+        foreach ($result as $key => $value) {
+            $newColumns[$key] = $value;
+            if ($key === 'price') {
+                $newColumns['cost'] = 'col-cost';
+            }
+        }
+
+        return $newColumns;
+    }
+
+    /**
+     * Add HTML rendering for cost column
+     *
+     * @param \Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer $subject
+     * @param string $result
+     * @param \Magento\Sales\Model\Order\Item $item
+     * @param string $column
+     * @return string
+     */
+    public function afterGetColumnHtml($subject, $result, $item, $column)
+    {
+        if ($column === 'cost') {
+            try {
+                $product = $this->productRepository->getById($item->getProductId());
+                $cost = $product->getCost();
+                if ($cost) {
+                    return $subject->getOrder()->formatPrice($cost);
+                } else {
+                    return __('N/A');
+                }
+            } catch (NoSuchEntityException $e) {
+                return __('N/A');
+            }
+        }
+
+        // Make product name and SKU clickable
+        if ($column === 'product') {
+            $productUrl = $subject->getUrl('catalog/product/edit', ['id' => $item->getProductId()]);
+            
+            // Replace product name with linked version
+            $productName = $item->getName();
+            $linkedName = '<a href="' . $productUrl . '" target="_blank" title="' . __('Edit Product') . '">' 
+                        . $subject->escapeHtml($productName) . '</a>';
+            $result = str_replace($subject->escapeHtml($productName), $linkedName, $result);
+            
+            // Replace SKU with linked version  
+            $sku = $item->getSku();
+            $linkedSku = '<a href="' . $productUrl . '" target="_blank" title="' . __('Edit Product') . '">' 
+                       . $subject->escapeHtml($sku) . '</a>';
+            $result = str_replace($subject->escapeHtml($sku), $linkedSku, $result);
+        }
+
+        return $result;
+    }
+
+    /**
+     * Add column header for cost
+     *
+     * @param \Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer $subject
+     * @param string $result
+     * @param string $columnName
+     * @return string
+     */
+    public function afterGetHeaderText($subject, $result, $columnName)
+    {
+        if ($columnName === 'cost') {
+            return __('Cost');
+        }
+        return $result;
+    }
+}

Plugin/Order/View/ItemsColumns.php

@@ -0,0 +1,30 @@
+<?php
+namespace Shopkeeper\OrderItemsCustom\Plugin\Order\View;
+
+class ItemsColumns
+{
+    /**
+     * Modify the columns array to remove tax columns and add cost column
+     *
+     * @param \Magento\Sales\Block\Adminhtml\Order\View\Items $subject
+     * @param array $result
+     * @return array
+     */
+    public function afterGetColumns($subject, $result)
+    {
+        // Remove tax columns
+        unset($result['tax-amount']);
+        unset($result['tax-percent']);
+
+        // Add cost column after price
+        $newColumns = [];
+        foreach ($result as $key => $value) {
+            $newColumns[$key] = $value;
+            if ($key === 'price') {
+                $newColumns['cost'] = 'Cost';
+            }
+        }
+
+        return $newColumns;
+    }
+}

etc/adminhtml/di.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
+    <type name="Magento\Sales\Block\Adminhtml\Order\View\Items\Renderer\DefaultRenderer">
+        <plugin name="shopkeeper_order_items_custom" 
+                type="Shopkeeper\OrderItemsCustom\Plugin\Order\View\Items\Renderer\DefaultRenderer" 
+                sortOrder="10"/>
+    </type>
+    <type name="Magento\Sales\Block\Adminhtml\Order\View\Items">
+        <plugin name="shopkeeper_order_items_columns" 
+                type="Shopkeeper\OrderItemsCustom\Plugin\Order\View\ItemsColumns" 
+                sortOrder="10"/>
+    </type>
+</config>

etc/module.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
+        xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
+    <module name="Shopkeeper_OrderItemsCustom" setup_version="1.0.0">
+        <sequence>
+            <module name="Magento_Sales"/>
+        </sequence>
+    </module>
+</config>

registration.php

@@ -0,0 +1,8 @@
+<?php
+use Magento\Framework\Component\ComponentRegistrar;
+
+ComponentRegistrar::register(
+    ComponentRegistrar::MODULE,
+    'Shopkeeper_OrderItemsCustom',
+    __DIR__
+);