Nobody Knows (Prequel)
From Queen2408 via MyAnimeList:
Renji and Kenta are musicians, they meet each other thanks to the friendship between their bands. Each musician has different reasons to play, be it love for the music, a strong desire to surpass their fears on stage or even just for someone’s approbation.
While these bands are struggling to be known in such a competitive world, Kenta is struggling with a different problem in his love life; can he be a replacement for someone else?