Dropout kara no Saishuushoku Saki wa, Isekai no Saikyou Kishidan deshita

Violinist Masumi Todo gave up her professional career after failing in an international competition. Despite her disappointment, she is unable to give up the violin, but one day she suddenly falls down a flight of stairs and is lost in another world. In the midst of the confusion, she is accused of espionage and taken to a place where she is forced to explain herself to the Knight Commander Arc. In a situation of absolute desperation, Masumi's destiny is illuminated by a “violin” that has come to the other world with her.

Original Web Serialization
Original Web Novel: Kakuyomu, Syosetu

https://www.cmoa.jp/title/294875/