A data leak suggests upwards of 110,000 pre-orders in the first 90 minutes. That doesn't sound like enough traffic to break the store page. 512 GB model outsold the other two combined.
https://arstechnica.com/gaming/2021...mpse-of-steam-decks-initial-preorder-numbers/
https://arstechnica.com/gaming/2021...mpse-of-steam-decks-initial-preorder-numbers/