Optimise Appsheet for warehouse use for complex picking

I have an excel workbook with 4 worksheets. Each sheet has 20 columns and up to 5,000 rows of data.
Tha AppSheet app is used in the warehouse to pick science kits for schools. Each tray has different components which may vary in quantity depending on the school size and the science lesson. The lesson is scanned and the appropriate details are shown in the app. By pressing coded buttons the number of items is picked, then confirmed which then count the tray as picked.
Ideally, the stock left would be recorded, however, this slows the app considerably so is done twice a day outside the app. The stock is recorded on a different app.
Four or five pickers are working at the same time using tablets. The concept seems to work Ok, but syncing the data slows the picking speed.
Attached are the two excel files used. Empiribox Picking is the data used by the Picking App.
I have two requests:
1) Is the table set out in the most efficient way.
2) How can I speed up syncing.