The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
I used the Arcade plugin for the main flute melody: chopped, processed, pitch, play with the tune.
I made the Saxophone in the same way
Sample pack Arcade
Loop name Arcade - Drip Section - Mob Flute