Facing the same issue… Did you find any solution?
Ideally it will be great d if we can completely hide the out of stock from appearing on the specific store POS Menu. So staff will need to browse through less items before they find the correct one (for items with no barcodes) But if not, so at least not being able to add it to cart will be a good start.
I think Shopify POS developers should work with actual Retails staff to understand our needs better.
There are also issues with the Auto barcodes which goes to the wrong section of Internationally recognized barcode rather than internal SKU. That get you suspended from Google merchant.