I’m a bit confused: so your account isn’t “home country” now? What is it, and why doesn’t that work?
From the beginning with Steam, I’ve just been signed up with a Taiwanese credit card, and it expects me to be in Taiwan. I don’t remember if I’ve ever tried to buy anything when I’ve been outside Taiwan.
I resolved my problem by using a VPN on my phone and then signing in and buying the game and now I can play the game on my computer or wherever while in Taiwan.