Same problem here. Is there any solution?
I like the game, would love to buy the (full) early access game.
The easiest way is to ask someone in another country to create a Steam account for you in their region (or create one yourself and purchase a region changer). There are many websites online where you can top up a Steam account for almost any region. I use this method for my second account with a foreign region and top it up through FunPay (not necessarily through this site). I've been using it for several years now and have never had any problems with purchases. I live in Berlin and use this method to bypass this restriction on Steam.