Hi, and welcome to the forum
Most music from films like this is composed and created by people who do this for a living. The music may seem familiar, but it usually isn't, rather it is "original" scoring that most likely never made it to a soundtrack or even published.
The reason it would most likely not be anything previously composed/performed is that the film producers would have to pay 'royalties' to the composer as well as all the musicians who recorded the piece, every time the piece was played or used. This would become a very very expensive proposition and most producers can (and will) hire somebody to create this music for lots less money.
It's a beautiful cut of music no doubt about it ... but most likely 'stock' music created for such films.