So, I got a final response from Customer Support on the Shiny Event.

"Thank you for contacting Pokémon Support regarding the Shiny Koraidon and Shiny Miraidon promotion for Pokémon Scarlet and Pokémon Violet.

All details regarding how to obtain and use the code for Shiny Koraidon and Shiny Miraidon are available here: https://www.pokemon.com/us/pokemon-news/get-shiny-koraidon-or-shiny-miraidon-at-gamestop-and-eb-games. Please note that no purchase is required for this promotion, but the offer is only available while supplies last.

Customer support doesn’t have any other details so we may not respond to further inquiries regarding this same topic.

Thank you for supporting Pokémon!"

So, customer support has no more information. They also will not be responding to further inquires. I never got a single NON automated response.