Romans 1:19-20 says that no one Christian or not has any excuse, but will be judged by God.
Romans 2 is more about there being no difference between Christians from the Jews or Christians from the Greeks.
Verses 11&12 : “There is no partiality with God. All who sin outside the law will also perish without reference to it, and all who sin under the law will be judged in accordance with it.”
This is talking about Christian Greeks not knowing the law as well as Christian Jews, but this will not matter for God will judge each in their own situation.
This is about those two Christian groups that were at odds at the time, but is a very general principle as indicated by Romans 1:19-20
