Aussie physical retailers do not seem to stock this game.

No one stocks the game anymore, it hasnt been reprinted in years. Ubisoft actually cut the print run short and released a ton of "boxed copies" that didnt even have a cart, they just included a download code.

Best bet would be trying Amazon US or ebay and see who ships internationally.

https://www.amazon.com/Family-Feud-Nintendo-Switch-Standard/dp/B08L91Z6VK?th=1

https://www.ebay.com/itm/195714192440 (this one is only $32 USD after $15 shipping to Australia.)