In fact, the whole story was "invented" by Max, and 19 was a character he imagined. It really makes sense to understand movies in this way.
If director Giuseppe Tonatore tells it from a third-person perspective, then 19 must be "real". But told by Max, a "comparative role", Max's personal feelings have become an indispensable factor.
Max didn't meet him until he was an adult in 19, so his childhood in 19 became "second-hand information". According to Max, 19 learned the piano without a teacher. This is obviously unreasonable. There must be a teacher in 19, but Max didn't know the details, so he simply called 19 a musical prodigy.
The plot of his meeting with 19 is obviously exaggerated. As we all know, in 19, the "drifting to play the piano" was a "movie". In reality, the piano would have hit the wall.
Extended information:
Life of the character in 19:
In 19, an orphan was abandoned in the first class on the luxury cruise ship Virginian, and was raised by the sailors on board, named 19. In 19, he grew up slowly, showing his extraordinary piano talent. The band on the ship performed the piano, and everyone who heard him play was deeply moved.
Jenny, the originator of jazz, heard about the superb skills of 19, and went on a boat to compete with him. At last, she sighed and left sadly. Unfortunately, all this happened at sea.
19 never wanted to set foot on land, until one day, he fell in love with a girl and his feelings flowed on the keys. Will he set foot on land to start a new life for love and surprise the world with his piano? How he will compose his extraordinary life.