Work that will reminded you of Usui Shio sensei.
The time skip in the end feel a little rushed but understandable since both are asexual and one aromantic, they keep a distance and become "best friend forever".
There's no love line progression in their lives, unlike her side couple.

For the record, the type of music Matoi does is called "Industrial Music". The manipulation part of industrial music, came from a branch of modern classical music called "minimalist music" started in the 1960s when someone discovered that you can keep a recording tape playing non stop by looping the beginning and the end of the tape, and later, intentionally run it faster or slower while playing it. Then duplicate the tape and now play both looped tapes together but with different speed. It is called Minimalist because you can play 30 tapes together in different speed but each tape only plays the same 6 or 7 notes musical phrase again and again. Meanwhile the Sound part of the Industrial music started in 1970s England. Performing music using whatever things you find in your daily life. or in a factory. or on a beach during holidays. Or performing live by creating sounds on stage using metal smith's tools and materials. The music being called industrial is because most of the sound created are by the working of metal tools in a factory machine. Then sound will then be recorded, and the tapes will be manipulated. When sampling machines were invented, this made industrial musicians the ability to do a whole lot more manipulations of sounds. A lot of these sampling machines has a keyboard. Thus you can create a "proper" song. Later on sampling computer programs were invented. This allowed manipulations to be programed and created numerous types of variations which nobody could imagined could be possible. What Matoi does, is using this method. Record the sound into a digital recorder, then upload it into a computer, run the sampling program, and then download the results so that people can hear the music. Modern industrial music is now frequently played in dance clubs, as one of the most easily recognized sound of an industrial piece is the booming bass and beat. Matoi's different. Her music would be considered as "experimental industrial music", since she only considers sound being important, whether the result turns into a conventional piece of music is not what she is looking for. If the song sounds good, great; if not, as long as the sounds are interesting, then that will be a good result. That is why she recorded sounds of non professional singers like Yuriko or her parents. In her mind, she was recording human voice, not songs.

Thank you for educating us.
It's an eye-opener to understand more of what MC does.

the art is really nice, not too moe but not too old-school.

It actually is old-school, just not yuri old-school. The author is a yaoi artist, and it shows, lol. Long arms, large hands with long fingers, long faces with sharp features, particularly the sharp chins, it gives a rather stereotypically masculine appearance (in terms of manga looks) to the characters. Mind you, I dig this, it is good stuff.

3 Years later, but Renmei is not a yaoi artist lol. This work is from 2018, there is not a year of publication but 5 years ago (2020) another yuri one-shot by her was scanned, her first and only yaoi work is from 2021. The characteristic you are describing, long arms, long fingers and sharp features are typical of shojo and most genres derived from it. Before Yuru Yuri and its moe impact to this day on the genre, most yuri also had those characteristics as one can seen in most stories in the old-school tag