Can't Purchase Marketplace Item Outside US

I'm unable to add any payment information as when it requests an address it doesn't allow me to input any options outside of the US - this is an issue as I am based in Australia.

This is in the Minecraft Marketplace selected through the bedrock edition launcher. I have tried to add a VISA card and a paypal account - both with the same result. I have also tried to both buy add-ons directly and purchasing minecoins.

Possibly this is because I'm playing through a family sharing GamePass account? But that is only how I launch the game, I also own Minecraft myself.