one downloadable virtual product with 1000 unique pieces

Hi,

We are a startup company and we have been struggling to find a solution for the following:

We basically have one downloadable, virtual product of which we have
several (1000’s) unique copies (files). Each (copy) file has its unique serial no. and there is only one copy of each file.

We would like to display it in our shop as one single ‘generic’ product . Clients
can then add 1 or several copies of this product to their cart.

The download links that they receive in the confirmation email are all, unique single files holding a unique serial no.

We have tried setting up a single product with many copies and adding
the download links but when a customer even buys just only a single
copy, he can download all the other copies as well.

We have tried to work with an attribute and then each file in a variations but in the cart the customer can not choose several copies. In another setting he could choose several copies but when receiving the confirmation email with the download files, he would receive just one link with one file and not the amount he selected in his cart.

Many thanks in advance!