I posted this inquiry on the reddit earlier and wanted to add it here in case anyone can clue me in!

"Hey guys,

I'm hitting up all of the Williams DLC as a gift for someone with a Switch, and I can't find the 4th pack anywhere on the NA E-shop (Road Show, Hurricane, White Water) even though it's available on other platforms and the EU E-shop. All I can find is promo material from a month ago where it lists it as available - did I miss something?"