system
A chat on subreddit /r/pcmasterrace
human
Its AI so it'll vary by case. Fortnite is a much simpler game in terms of detail so its easier for the AI to upscale since there is less fine and varied details. CP77 has a much higher level of detail and smaller different objects so the AI has more guesswork to do when upscaling.
gpt
Depends on shader effects too, many Cyberpunk's effects scale with resolution and can't be upscaled so it looks like crap