Plot

I read up to where your story ends, and so far the plot hasn't really gotten anywhere, at least when it comes to conflict. One thing I want to mention is that I feel like certain chapters can be joined together, many are very short, and while it may be easier to read, you'll only end up with 10 chapters that don't go anywhere, and 50 before you even get to the juicy stuff. I recommend combining some of them to make them longer and not having as many chapters. With that being said, I'll move onto the actual plot.

What you've got going is pretty good so far. I feel like the beginning was a bit rushed, and the whole fight scene seemed really out of place. It only felt like it was there just to introduce Jamie, but serves no other purpose. If it has a bigger significance later on, then nevermind this note, but I feel like Jamie's introduction to Kai could be executed better, less dramatic.

I enjoyed reading your story, as nothing really felt boring or too slow paced. I feel like certain scenes could be more descriptive and longer to really make it even more interesting, like when Kai plays the violin for the first time in years. That's a major moment, and I think it could be even more emotional and bigger. But, that's really my only main critique. Other than that, I like your writing style so far and I think you have something going.

Characters

I think so far your characters and their development isn't bad, although they could be improved. I like Al's character, she seems pretty thought out and developed and has a lot of, well, character. Kai, on the other hand, seems a bit flat. The only thing personality wise we know about him is that he's socially awkward and has a rough family life. His personality just doesn't seem as strong or clear compared to Al. Since these are really the only two main characters at the moment, I'll only really focus on them. The parents and the little we know about Jamie doesn't really include enough to critique. Some things to possibly consider when developing and forming characters is to think about their motivations. Why did they do this and that? What do they want, how are they going to get it, and why do they want it? Their goals, ultimately, and the motivation for those goals. And even the smallest of details: what do they like and dislike? What's their favorite food or color (something like that)? Little things like that that may not even be shown in the story can help form a character. Make them real, and make them relatable. In some way, a reader should be able to understand, connect, or relate to your characters.

Those are just my ideas and tips as far as characterization, but you can do whatever you want. It's your story, so take my advice with a grain of salt.

Extra

These aren't the main focus points, so I won't elaborate on them too much, just some extra critiques:

-I generally would avoid slang in writing. Nobody really says or thinks to themselves "bombastic side eye" or "sussy baka". It sounds better in your head...
-There are some frequent grammatical errors, so just make sure to proof read.
-Separate your dialogue, don't have two or more people talking in one paragraph. It gets wordy and difficult to understand who is talking.

I think with some improvements and editing, you've got a pretty interesting story going. As I said, I enjoyed reading your book and I hope you continue to add onto it! Good luck on your writing and thank you for letting me review your book.