try to get it work

admin/src/Model/DepotModel.php

@@ -0,0 +1,29 @@
+<?php
+/**
+ * @package		Depot.Administrator
+ * @subpackage	com_depot
+ * @author		Thomas Kuschel <thomas@kuschel.at>
+ * @copyright	(C) 2023 KW4NZ, <https://www.kuschel.at>
+ * @license		GNU General Public License version 2 or later; see LICENSE.md
+ * @since		0.0.3
+ */
+
+namespace KW4NZ\Component\Depot\Administrator\Model;
+
+use Joomla\CMS\MVC\Model\AdminModel;
+
+\defined('_JEXEC') or die;
+
+class DepotModel extends AdminModel
+{
+	public function getForm($data = [], $loadData = true)
+	{
+		$form = $this->loadForm('com_depot.part', 'part', ['control' => 'jform', 'load_data' => $loadData]);
+
+		if (empty($form)) {
+			return false;
+		}
+
+		return $form;
+	}
+}

admin/src/Model/PartModel.php

@@ -26,4 +26,4 @@ class PartModel extends AdminModel
 
 		return $form;
 	}
-}
+}