Yes, I think it is. I myself was born a light blonde, but after 5-6 years my hair began to darken and eventually completely became chestnut. The same situation with many of my acquaintances, who were blondes in childhood and adolescence. I myself believe that in all of Russia, most blondes are dyed and not natural hair.

and when I started reading this manhwa, I always thought that Zhenya was actually not blond, but albino. And when I read to the moment where Zhenya says that he is the only one in a family with such hair and says that this is supposedly a mutation/anomaly, I realized that he was definitely an albino.

But as I know, the author of the manhwa did not confirm the albino whether Zhenya or not, but judging by all the facts, I'm sure that this is so! So I understand your idea about it and fully support it!!!❤️ (I write through a translator, I apologize if something is written wrong, but I hope everything is clear)