With the release of the Steam Deck OLED and the Steam Deck OLED Limited Edition tomorrow, Valve has given out a little bit more info on how they plan to combat scalpers.
Some desperate scalpers on ebay are already trying to sell the 512GB version for 1000€. Despite the fact that you can still order one for half the price and receive it within 6-10 days.
I could be wrong, but I would bet that launderers are probably not targeting this niche device. I'd guess that the people buying them are more likely from a country that they don't sell in. Like Australia for example.