so my theory is phi is in a different school and is ❤️. phi cannot be non's brother since non's brother goes to a university and here phi is wearing a school uniform (but the code on his shirt is different, which means he goes to a different school). him and non have a thing going on and maybe after non's "disappearance" phi decided to take revenge so he moved to non's school (in grade 12). maybe he fell in love with jin in the process or maybe it was part of his revenge plan after all. or maybe jin is in on the whole thing and is helping phi get justice for non in the present.
still unsure about the teacher character, but let's see where that goes
what's the symbolism with the golden fishes and fishbolws (? idk if thats the correct word) lately lol
it's a reference to baz luhrmann's romeo and juliet. there's an inconic scene in the movie where leo and claire stare at each other through a fish tank and it's been referenced in a lot of gay media lately (euphoria for example). so it's just a little nod to that. i think there was also a car scene which was a nod to wong kar wai's happy together.
if you cut all the cringy stuff, the childhood best friends/crush to lovers plotline was actually really sweet and chanyeol gave it his all into the role. i even liked the love triangle, wish d.o and chanyeol had more heart to heart scenes though.
still unsure about the teacher character, but let's see where that goes