I would diiie if this were made into an anime 😭
There is a minor historical composer named "Giovanni Bazzoni," but I think in the manga the composer is based on the (fantastic) Italian cellist-composer, Giovanni Sollima, and I totally headcanon that this is the song that Tetsuo is obsessed with in the first volume: https://youtu.be/lRlPpv0V3BE?t=90 (the older guy playing is Sollima himself)