I brought a Stadia Premiere Edition... It came with everything but not the code.
Code is sent via email to the account that purchased the bundle usually around the time of delivery. Check spam folders to see if it is buried somewhere. Failing that, you can contact support and provide then with your order number (you can find that on Google Store if you don't have the original details to hand, and you will also need to supply them with the serial number of your Chromecast Ultra.