@PDotWee Looking at the pinned post, it seems the only info we have is they're still being rolled in the sequence in which they received pre-orders:
https://community.stadia.com/t5/Stadia-General/Ordered-6th-of-june-yet-to-recieve-a-code/td-p/255
Thats so dumb. How hard is it to add a activation code to the system. They are auto generated, Google Stadia is terrible so far!