A suggestion to make them better would maybe be to time lock them. 5 min after the stream. Even if someone shared them, the likelihood of finding them on forums, chats, or discord wouldn’t be feasible for a lot of players by the time they got over to the web store. That way people don’t have time to do digging and keep formulating guesses. If they still remain unguessed, then limit them to 1 entry.
As far as these secret codes were concerned…I thought I had at least one for sure…no dice