I highly appreciate the details you've included in your post and the screenshot you've provided, @Akervin. I've got a way to help you change all the items in bulk. No worries, let's work together to achieve this.

In QuickBooks Online (QBO), we can utilize the Advanced Search feature to streamline the process of adjusting your inventory quantities. This way, you can quickly identify the items that need adjustments. This feature allows you to search and filter through your inventory items efficiently.

1. Look for the Search tab, then click Advanced search.
2. From the All Transactions dropdown, select Inventory Quantity Adjustment.
3. In the Inventory adjustment account dropdown, select the appropriate account.
4. Select Search, then select the adjustment you want to edit. This opens the inventory quantity adjustment. You can add new adjustments, edit previous adjustments, or delete them.

To edit previous adjustments:

• Change the Adjustment date and the Inventory adjustment account if necessary.
• Edit the details in the Previous adjustments section.
  
  

To add new adjustments: 

• Enter the details in the New adjustments section.

To delete: 

• Select Delete.
• (Optional) Enter a note explaining why you edited the adjustment in the Memo field.
• Once done, select Save and close.

For visual reference, I've added a screenshot below:

By doing this, you can optimize your workflow, making the task of updating inventory levels more manageable and less time-consuming.

In addition, I'll be dropping this helpful article for you to learn how to check your inventory so you can always have an accurate inventory count: Fix negative inventory issues in QuickBooks Online.

Should you need further assistance or have additional queries about your inventory adjustment, please don't hesitate to reach out, @Akervin. I want to ensure that everything is taken care of just for you.