You have an "Add Stock" button that the user can use to add items in their inventory, these are done one at a time. I would suggest that you move that button out to the inventory page, next to or bellow the Create Order button, and allow the user to select all items of which they want to add stock. This is referred to as a "Purchase Order" in other inventory software.
You may need to allow the user to specify the quantity of each item they are adding. Also adding a report that will allow you to those past "Add Stock's".
This is the only problem I am having in switching to this software. I am enjoying every other aspect of this system and hope you are able or willing to solve this, somewhat, minor issue.
Thank you for sharing this idea. We are considering adding a procurement model which will solve for the purchase orders. I will take your feedback to the product team and see if we can implement this flow. I’ll reach out to you via email as soon as I have an update.