You can't simply go to the My Nintendo Store and buy the Switch 2. To order the Switch 2, you need to log in with an active, paid Nintendo Switch Online account. Once you do that, you can choose either a Switch 2 standalone console or the Mario Kart World bundle and then hit the confirm button to "register your interest" in ordering a Switch 2.

Nintendo’s new Switch 2 console smashed sales records and raced off store shelves, with more than 3.5 million units sold in its first four days on sale.