D.R.- my readng of Paul is that any Gentile who placed himself under the law was under obligation to obey it in the same way as a Jew - Galatians 3:10, Galatians 5:3 - “every man who lets himself be circumcised … is required to to obey the whole law”.

But doesn’t Paul make it quite clear in Romans 2, that he is talking about Gentiles outside the law? Eg Romans 2:12, Romans 2:14 - “Indeed when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves”.

When did Gentiles do by nature things required by the law? When they received the Spirit after hearing the gospel - “And so he condemned sin in the flesh (of Jesus) in order that the righteous requirements of the law might be fulfilled in us, who do not live according to the flesh, but according to the Spirit” - Romans 8:3b.