The Polgar sisters are very well known. The more you learn, the more you will agree "painstakingly hard" is an apt description.

Hard work will get you there, and in their case, hard work meant they were literally born and raised as human chess-playing experiments.

That article agrees with what the parent poster said, based on my skimming it. That article documents the great lengths those women, and their parents, went through to achieve their mastery. It also indicates their may be cognitive differences between high-level chess players and good amateurs.