The name of the song is Diving Bell: The Mechanic, by Mark Isham. The picture below is a screenshot from the end of the film, which is the Diving Bell section.

Amazon has the soundtrack of the movie, mechanical resurrection soundtrack, with 21 songs, the last one is this.

The movie soundtrack is by Mark Isham, as is "The Machinist". Other movie soundtracks include "Crash", "Warrior", etc., and the American TV series "Once Upon a Time", etc. Mark Isham was born on September 7, 1951, in a musical family in New York. In his early years, he served as a trumpet player in the San Francisco Opera Orchestra. He recorded his debut album in the late 1970s, formed an avant-garde jazz band in early 1979, and began a solo career in 1983. Isham was nominated for an Oscar in 1992 and won an Emmy Award in 1997 for the television series 'EZ Streets'. In addition to film scores, Isham has produced several jazz albums.