Remove the unused 'Order configuration' page, all configuration will be per order type.

modules/order/commerce_order.links.menu.yml

-commerce_order.order_configuration:
-  title: Order configuration
-  route_name: commerce_order.order_configuration
-  parent: commerce.configuration
-  description: 'Configure your order settings.'
-  weight: 10
-
 entity.commerce_order.collection:
   title: Orders
   route_name: entity.commerce_order.collection
@@ -14,5 +7,5 @@ entity.commerce_order.collection:
 entity.commerce_order_type.collection:
   title: Order types
   route_name: entity.commerce_order_type.collection
-  parent: commerce_order.order_configuration
+  parent: commerce.configuration
   description: 'Manage your order types.'

modules/order/commerce_order.routing.yml

-commerce_order.order_configuration:
-  path: '/admin/commerce/config/order'
-  defaults:
-    _controller: '\Drupal\system\Controller\SystemController::systemAdminMenuBlockPage'
-    _title: 'Order configuration'
-  requirements:
-    _permission: 'access administration pages'
-
 entity.commerce_order.add_page:
   path: '/admin/commerce/orders/add'
   defaults: