Well uh, a few things before I give a verdict here:
The plot does eventually change it up. Although I'd say if you're dismissing the stories so far as fairy tales/fables, even what the plot eventually becomes may be still have that vibe? (I honestly don't know what you're on about, but the game is tonally consistent for the most part. Also, for what it's worth, the game's not telling you these stories for no reason.)
Also, it's a visual novel, not a traditional game or even an ace attorney scenario, forget any pre-conceptions about playing anything. There are more choices more frequently later that are a bit more meaningful, but they're a means to an end to tell the story, rather than being there to be fun and engaging. It's a book with a bigger budget, that allows for a soundtrack and art assets. That's the package, basically.
If you feel like you've been just approaching this in the wrong frame of mind, then I'd say to try chapter 3? It's a little bit different from the previous two chapters in a few subtle ways, so you might latch onto something of substance there that allows you to get through the novel, and the quality does generally trend upwards as you go through. But it's not like a 1/10 to a 10/10 difference, so if you hated doors 1 and 2 in their entirety and found nothing enjoyable about them at all, it might not be for you.
I don't have anything against fairy tales, but the quality of the stories themselves is extremely low, whether by modern (Gaiman) or classic (Grimm, Aesop) standards. Worse, what ought to be a few pages (probably paragraphs) of content is stretched out to multiple hours. That might be forgivable if the writing were clever or engaging, but instead it is puerile even by video game standards.
I didn't realize there was a demo; else I might have saved myself some cash if not time.