That was a nice chapter. The face of Mitsuru when Erina says "I might even fall for you..." is priceless. Kusaka's transformation on stage shows his love for music makes him go forward when life hits hard. I like how he's becoming aware of the toxicity of Haruki.
By the way, you put Oneshot in the tittle, but this is chapter 19. (I just saw it has been corrected
)
As always, thank you for the translation!