How to create a digital product download link that can’t be used twice?

The goal is after people payed (paypall or Stripe), they land on a download page.

You upload the file to /uploads for example. You can deny access to the dir with .htaccess.

I suppose if I then create a link /uploads/product, that a client can download it.

But that link can now be shared all over the internet.

What would be the best way to go about it?

I want do code it myself in PHP & JS if required.