Romans 2:12

‘For as many as have sinned without law will also perish without the law, and as many as have sinned under the law will be judged by the law,'

The principle is simple. All will be judged on the basis of whether they have sinned or not. Those who are Gentiles and have sinned outside the Law of Moses will perish outside the Law of Moses. They will be judged by the light that they have. But they will still be found guilty and punished. They will still necessarily perish because they have sinned. Similarly those who have sinned under the Law will be judged by the Law. They too will be found guilty and will perish.