You’re making the common mistake of confusing realism with reality. They are not the same thing. Realism in this context is simply the idea of making things believable rather than just throwing random ideas into the game world like confetti.
It’s the difference between the Harry Potter everyone knows and “And then Harry turned his wand into a bazooka and shot bunny rabbits at the spaghetti fueled corvette the alien queen stole from Gandalf, who was busy fighting rock people from dimension 57.”
Basically, it doesn’t matter if something doesn’t exist or works differently in reality. It just has to make sense within the world that it is present in.
It makes perfect sense to me that in a video game the sun may not follow the rules. Crocodiles not being able to swim is a bit odd but who cares really, we have bigger problems to deal with and considering how limited time the devs have and how many issues there are to be fixed, I would rather have them work on those than fixing the direction of the sun which allegedly breaks the immersion for a handful of people.
So fixing it would be easy, maybe not a rotating sky.
For me the interesting thing is that i feel it at all. I played so many games and Conan is actually the first game, that does this. It is not a big deal, but while playing i found myself looking at shadows or the sky for orientation, just like i am used to in real life. Thats how realistic computergames have become which is amazing (i am sure there are games and simulations that are even more realistic). So yes, i feel this (i am even a bit proud of it, considering the growing number of people who never see the sky) and i want to remind the developers that this is a thing.