TL;DR : just call support that you didn’t get your code and they’ll send it.
I took a chance and just called Best Buy support (came up on my Pixel as Best Buy Express) and explained the situation regarding the Tech Test code and not getting it. Lady explains that they’ll forward the request and it’ll be sent in 24/48 hours. Wtf?!?! So after using some passive aggressiveness she said she heard of someone getting it within 20 min of calling. Sure enough same happened for me.
Idk why I didn’t get it yet or why it took a call to support to have it finally sent. At least there is a way to get the code if it wasn’t emailed to you already.