Hi vectra
Perhaps you can do so with our Stock Takes add-on.
You could scan your products one by one (with a connected barcode scanner), search them by barcode (by selecting the "Barcode" column), adjust stock quantities as needed, and reconcile the stock.
You can try out the trial version to find out if it's suitable for you.
And you can also read its documentation here:
https://stockmanagementlabs.crunch.help/en/atum-stock-takes
If you have further questions, please let me know.
Best Regards,
Salva.