Aug 18, 2021
Here's a longer comment :)
First of all, this is not nearly as bad as you seemed to think it was :) There's actually a lot of good things about it: some decent comedy, a couple of likeable characters, and several nice ideas. It's not like it's the most original thing ever, but it executes several of the things it does really well and that's already good enough in my opinion. It basically does a lot of what it's supposed to, which very much is a good thing.
That said, I figure you may want some sort of actual feedback too instead of just a generic "everything is pretty good", so I'll give some thoughts on stuff I had while reading and you can judge for yourself what seems useful or not.
First of all, just a comment on reader expectations for a certain genre. These are set by the cover, the blurb, the first few chapters, etc. There are stories that subvert these and do it well, but there's a good chance you'll lose readers by doing so, unless the people reading are a fan of both your initial premise and what it changed to.
In particular, what's relevant for this novel would be the division between when it was just a highschool romcom light novel and when the slight mystery stuff was added. Some people will be into the former, some the latter, and some both, and what those groups of people will want from a story is obviously different.
Particularly where I think some may just not feel like it's their kind of story anymore, regardless of being good or bad: The last scene in the chapter before the std was introduced happened very fast compared to the pacing of a typical romcom light novel, where some of the development near the end of it would probably have taken place several chapters later. So, I think that kind of thing may make you lose some readers that just want a normal highschool romcom light novel experience once the story diverts from that, which isn't in itself good or bad or even reflective of your writing: It's just a matter of people wanting different things, which will be unavoidable. Not everyone will like your story or want to read it all the way through. Basically, you'll be losing some subset of readers along the way almost no matter what you do, but that doesn't in itself mean your writing has to be bad.
That said, for people who actually are part of the target audience(I'd say I'm probably one of them based on my reading) I think what I could comment on would be:
1. As mentioned, the pacing of the chapter before the std got a bit faster than conventional near the end. It's really just like, the last third of it or so that probably felt like it could have gone a tiny bit slower and maybe had a little bit more build-up.
2. A lot of the scenes have multiple characters together and it can be a bit hard to tell who's talking. Common approaches to solving that, I think, could for instance be dialogue tags, or giving some of the characters more individual scenes near the beginning to establish them more strongly in the readers' mind, or just giving the characters a more distinct voice in the way they speak(like, what kind of words they would use or not and stuff).
3. Not something that really hurts the reader experience, but you could probably run into trouble for some of the explicit references to other media(like oregairu or attack on titan) if your stuff ever becomes popular enough.
Finally, about this chapter, it was a pretty nice one :) Feels like it helped me a lot with establishing Sakura as her own more distinct character I could take interest in
