Mmm there is nothing about this author in the info, and I never heard nothing about him/her...mmm okey, I'll give this a chance
Pd. I read it, I recommend the romance tag...I think it need it...also it feel a bit to Bloom into You in some way
Naru really is like the protagonist. She put the work in once she decided to be open about her feelings. I really liked her a lot. To write a love letter to the one who she can't reach with her voice alone was so brilliant.
Hibiki never realized that she was the heroine of the story, the perfect match for the protagonist.
It's not bad, but the "I'm not good enough for her" development is such a tiresome trope ...
A far too realistic one though. It's very common for introverts to feel like they are dragging their extrovert friends down or are not worth the effort.
In this case she felt that she was just in the way of Naru's happiness, but that's more because Naru's words didnt reach her too well.