Buyer accounts being linked

[bobshop]

My amazon buyer accounts are somehow being linked and I cannot figure out how.

I am placing orders for items on restricted quantity. For every order I use HMA VPN and Safari which I reset and clear between orders and use private browsing. I use amazon gift cards (separate number for each account and order) purchased in cash as payment and for address amazon lockers.

Somehow they link the accounts. How is that possible?