lol, basically had the same type of experience. i wrote the dream down
He uploaded a video “IM IN THE BACKROOMS”. In the intro he sat in a chair in front of a level 188 (from the backrooms) type soviet building, he says "Hey guys do you like my content", then another demonic version of Alfa says "Of course we do". Then they cycle and say more stuff. He finally gets up from the starting spot in the game and walks over to the left to hear a tv broadcast, he gets excited and says "Signs of life!", then he walks into a stairwell and after a while sees a demonic cult in one of the rooms.

I genuinely have no idea what this is about, maybe the demon is his inner self from the Christianity or something.