You need not only the VPN but a US payment method. At the moment of the purchase of a game you can change country. But only with a game purchase because if you try with the Deck directly it says the shipping address cannot be outside your region (and it comes before the payment details).

In my case I live in Canada but I’m italian and in the past I already changed country few times in my steam profile. But this time i wanted to keep it in euros (because of games from keys retailers cheaper for europe, plus I have some extra money to spend in europe) and since I wasn’t interested in the LE I just created another account with the only purpose of buying the 512 GB Glossy OLED. But yeah to buy the LE I would have had to buy a random game with my canadian card and change country first and then I could have bought the deck.