So if you can’t buy them directly from Nintendo you’re shit outta luck cuz good luck finding anyone that sells them for retail price.
This is par for the course for basically any physical Nintendo product. Ninty is categorically allergic to manufacturing enough supply to satisfy demand and the resellers figured this out about 10-15y ago. Any limited production run product is almost immediately bought out on Amazon and the other big retailers websites and relisted at a markup on Amazon/eBay. If resellers smell blood in the water around a manufacturing run of a popular game (ie: Nintendo is close to selling through the available physical cartridge supply) they’ll buy that up and resell it too. Nintendo would rather their products be unavailable for however long it takes them to decide to manufacture more (usually somewhere between two and six months) than have excess stock on hand.