I wouldn't look too deep into weapon availiability yet. It's entirely possible that modular AR was simply easier for the dev to model/order/buy assets for. There's a massive aftermarket for AR parts, which contributes to models and schematics being readily availible, hell, you could probably just rip 3D printing schematics for some parts and stick it right into the game after some texturing and touchups. AK platform also got its own aftermarket going on, it's just not as popular. And yes, if the game takes place in Poland, it would make a lot of sense to have AR-based platforms, because those are pouring into the country right now, and Poland is actively switching to as much NATO-based weaponry as possible. If this is Poland, then we will probably see Beryl and MSBS at some point. That being said, the raiders are clearly ruskies (though yeah, their russian is ridiculous), and there are a LOT of AKs still in circulation on their side and still will be decades into the future. Just look at modern combatants still using old AK-47s, SKS and even god damn Mosin rifles.
It's a shame there's no narration whatsoever going on, but understandable as dev is focused on gameplay. But given it's a single dev and building what is clearly supposed to be a high-end game gameplaywise, with update frequency as-is... I'm honestly not holding my breath for this game to go far in next few years. There's just way too much for one guy to do.
I do hope however that current sex content is a placeholder, because as it is right now, it's nothing interesting to the point it can be completely skipped. Without any narration going on, it's just a random set of rape animations, which aren't terrible, but feel like a Skyrim mod. There's just no investment whatsoever.
And I really hope this game eventually gets some good writing. The gameplay deserves it, and from my experience, 3D action games that focus on gameplay get such utterly horrid writing that it would be 100% better if it wasn't even there.