We're facing the same problem as well. Until now we have asked our customers to create a Business Manager account per country, so that they can create and distribute codes themselves. Which is an absolute nightmare by the way. Everybody is sick about how Apple makes processes unnecessary complex.
Simple solution for Apple: make each VPP redemption code work for each country's App Store. Then global HQ only needs 1x Business Manager account and can distribute the codes easily to all her global employees.