So, out of nowhere, Ghost of Tsushima Director's Cut has been blocked for purchase in my country

Are you saying, that Sony is crap, so lets give them more of our money and buy their console as well?

You're touching onto something there. During the last days of turmoil I thought Sony's acting like a cornered rat. Sure, they're making excellent consumer hardware but somehow they lost against competition from South Korea and China. Although I don't believe the sentiment of pc gaming crowd results in more than a blimp on their balance sheet it's never a good thing to have negative brand perception.

it doesn't

Most Estonians set Finland as location

I get it, and I know that you already know this, but it’s not worth it. Maybe things will change in the future, but given your current situation, I think it’s best to just wait it out and see what happens.

I am a huge Remedy fan, and naturally, one of my most anticipated games is Alan Wake II. I’ve been waiting for that sequel for over a decade. Unfortunately for me, though, it’s exclusive to Epic Games Store. Will it ever come to Steam? It’s highly unlikely, since Epic Games fully funded the development of the game. My choices are simple: I can either 1) buy it on Epic Games Store, which I refuse to do because all my games are on Steam; 2) pirate it, which I won’t do because it’s not fair to Remedy, my favorite game studio; or 3) just wait. For now, I’m choosing to be patient.

One downside is that I would be locked in that store for 3 months, I believe. An even bigger downside is that I would be seriously risking a perm ban for account sharing and circumventing purchase restrictions.

That's correct. Difference would be if you were just traveling. 3 months lock down would still apply (in which you shouldn't buy anything to be absolutely safe), but you wouldn't have to break ToS.
But like ipax11 recommends: just wait. While Sony urgently refunded now to avoid legal consequences, they are surely interested in more sales and thus trying to improve the situation, yet that might take a lot of time. Take advantage of your backlog.

It's beyond stupid, and they made that right after the game director of Ghost of Tsushima told to the press that their game doesn't require PSN access for the single player part...
I'm Hungarian, I could buy it - but just out of protest I removed every PS-published game from my wishlist and set them all as "Ignored" after the Helldivers fiasco (and I didn't even plan to ever play Helldivers, it's not my cup of tea).

Why is that game so important that you contemplate doing half-legal things?
Just don't buy it, don't pirate it and spend your time on other more worthy devs/publishers games.

The arab gulf countries are not blocked.