There's no way to directly buy the game outside steam at the moment.
You can get a friend from a different country to gift you a steam key and it should work. That's the only method that works.
Alternatively.
If you have a patreon or subscribestar account, subscribe to Gold tier or higher. Then contact me over discord or email itchv19games@gmail.com (Or even a direct message in Patreon/Subs itself), send me the email or username you used to subscribe and I will send you a steam key.
This is the only way I can sell the game to people in Germany/Brazil at the moment.