Not available in your region? Here's the fix.

Copy the following link into a browser or just use Win+R and paste it in there: steam://install/24200 (apparently it works in Chrome too but "you just have to select the second option after you paste the link")

Install and wait for the game to download. It's about 25 gb, it might take a while.

You can now play the game, with all its Steam features, the store page, unfortunately, will remain unavailable, you won't be able to buy the DLCs on Steam yourself, but you can still get them through trading or from a friend from outside your country (since it is unavailable in yours). I tried it myself, it works.