My understanding (I'm in the US too) is that apps in many other countries don't even have a web app equivalent. If you want your money, you need an authentic android phone and a closed-source app. Or, you can buy a plane ticket somewhere else.

Most banking in for example Europe work fine with GrapheneOS, as long as you relock the bootloader. See e.g.: https://privsec.dev/posts/android/banking-applications-compa...