It's a simple world.
Just modern earth.
The only difference is that people have some special abilities. A remnant of the past.
A few centuries ago, half of the world's population vanished. Starting then was when people started developing abilities.
It was a bit different from abilities from fantasy worlds. No system or guidance like in the novels.
It simple manifested as talent.
The world continued to progress without much regard to the disappearance of people.
People could search for the truth. But there was no fantastical power to go on.
How simple would the matter have to be for it to be discovered by artistic or medical talent.