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.
The guitar is recorded by me and played by my incredibly talented brother :) Most of the melodic stuff is created with SERUM. Some of the sounds are samples but 100% royalty free. I layer the chords mostly with 3 layers, one for the mid-end, one for the high-end, and one for the low-mid range. All the drums are high quality samples which I processed through the mixertrack.
Instrument guitar sample
Sample pack FEVR - Soundkit vol. 1 (Free)
Loop name FEVR - Summer sample (86 BPM)