Good day to you, @gerdgoebel.
I appreciate you for sharing the details with me. I can see how convenient it is to import your build assembly item.
As of this time, there isn’t an option to import them in QuickBooks Desktop (QBDT) using Excel or CSV template. In QuickBooks, we can only import Inventory Parts. Then, you can create the Inventory Assembly items using the imported items.
Nevertheless, you can consider looking for a third-party app that lets you import assembly items in QBDT. You can go to the App Center on your software and look for an app from there. You can also visit our QuickBooks Apps Store for additional reference.
Let me also add this article that you can utilize in case you need to edit an item in QBDT: Add, edit, and delete items.
You can always keep in touch with me whenever you have other questions about inventories. I’m always here to lend a hand. Keep safe and take care!