I appreciate you getting back to us and performing the troubleshooting steps shared by my colleague above, @H2TackleOutdoors.

You're right. Importing inventory items can be imported without using the UOM option. Let's first re-sort the inventory list to get your inventory items imported in your QuickBooks Pro Desktop 2020 successfully. Then, import the inventory items again.

Here's how:

1. In your QuickBooks Desktop, click the Lists menu
2. Select Item List.                                                                                        
3. Click the arrow beside Item, then select Re-sort List.
4. Hit OK to confirm.                                                     

Here's an article you can read for more details: Re-sort lists.

Once done, you can now import your inventory items in QBDT. For your reference, you can check out this article for more guidance: Import or export MS Excel files.

You might also want to read this article to know how to adjust inventory quantity or value in QBDT.

If you need any additional assistance while managing inventory items, you can leave a comment below. I'll be sure to get back to you. Have a good one.