When you run it through a simple reverb and a touch of tape saturation, it doesn't sound like a performance. It sounds like a recollection of a performance. This is why it became the weapon of choice for "sad indie" scores and ASMR-adjacent relaxation tracks. It lacks the harsh attack of reality. It is a simulation of warmth, which, ironically, feels warmer than the real thing to a digital-native listener.
If the UI looks "messed up," ensure the Resources folder is in the same directory as the .nki patch. Free Alternatives (Truly Free) ilya efimov nylon guitar kontakt free work download