I've lost track of how many times I've cried because of this manga that I thought my tear ducts had to be broken or something. It really knows where to hit you hard. I think the most I cried was during the Sveta arc... Accompanied by the fluffy art style and dialogue, it is genuinely heartbreaking to me to see these characters come and go. The character development is also really, really good. Being able to learn a lot about these characters make me feel more attached to them, and makes me cry even harder when they inevitably die or get better.
I won't give it all praises though, there's definitely some issues with characters like Sik-sik just... disappearing? It is also very cliche at times with "le power of friendship" is the most important thing for power. While there is a ton of self-improvement on the emotional and psychological side of things, seeing them not train at all by improving their powers or anything makes it unrealistic to me and breaks some of my immersion. Like these special moves and powers just kinda get pulled out of their ass.
I would still really recommend reading it. Shy shows that even a 14 year old girl with an inferiority complex can muster up courage to do what they want to do.