Austria isn't an option, unfortunately. Best alternative seemed like Germany so he ends up in the right region as a free agent in Fire Promoter. I'll use Parts Unknown a lot when home countries aren't available as options, but being European is so central to his character and it would be odd seeing Gunther end up as a Latin American free agent.

Been a few month since I downloaded Gunther, but in game he is billed from Germany rather than Austria. Not sure if that is a mistake or the game doesn't have Austria as an option!