You and your exhaustive list:
Ignoring the issue will not cause it to go away, so please clearly state whether you think the list is exhaustive or not because it is self-contradictory for you to be trying to pick both.
Gentile believers have a conscience (Romans 2:14) and the teachings of Paul (Apostle to the Gentiles) and Paul does not instruct them to keep the Mosaic Law (outside the four thngs listed in Acts 21:25).
In Roman 2:13-15, Paul said that Gentiles are by nature doers of the Mosaic Law even though they do not have it and show that the work of the law is written on there hearts which their conscience also bears witness to, and their conflicting thoughts accuse or even excuse them. So Paul was not saying that Gentiles should just follow their conscience, but that Gentiles should be justified by being doers of the Mosaic Law and that their conscience bears witness that it is written on their hearts, which is in accordance with Ezekiel 36:26-27 and Jeremiah 31:33. In Romans 2:25-29, the way to recognize that a Gentile has a circumcised heart is by observing their obedience to the Mosaic Law, which is the same way to tell for a Jew (Deuteronomy 10:12-16), and circumcision of the heart is a matter of the Spirit, which is in contrast with Acts 7:51-53, where those with uncircumcised hearts resist the Spirit and do not obey the Mosaic Law.
The fact that there is overlap between the moral portions of the Mosaic Law and the two items (conscience and Paul's teachings), shows that a list of rules from the Mosaic Law is not necessary.
To suggest that there are moral portion of the Mosaic Law is to suggest that it is moral to disobey the other portions, however, there is no example in the Bible of disobedience to the Mosaic Law being considered to be moral. Rather, morality is in regard to what we ought to do and we ought to obey God, so all of His laws are inherently moral laws.
Our conscience part of our fallen nature, so it is not perfect, which is why Paul said in 1 Corinthians 4:3 that even though he was not aware of anything against himself he was not justified. So our conscience helps us to live in accordance with the Mosaic Law, but it does not replace it, and therefore is not the ultimate determiner of our spiritual condition. Our conscience is capable of warning us when our spiritual condition is in danger, but it is not the Mosaic Law, and needs to be informed by it in order to function correctly.
In Romans 14, there are weak Christians whose conscience is not informed in a mature way, where their conscience won't let them do what they really would be free to do, so again our conscience does not replace the Mosaic Law. Someone's conscience can be so misinformed that their glory is in their shame (Philippians 3:19), where both their mind and their conscience are defiled (Titus 1:15). So the first way to destroy the work of conscience is to misinform it where you don't give it the Mosaic Law and the second way is to silence it when it speaks. In 1 Timothy 4:2, Paul spoke about a wounded or seared conscience, and a good indicator of this is if someone doesn't feel convicted about continuing to do what God has revealed in His law to be sin.
Wrong, If you keep reading through Romans 3, you find that no one (other than Jesus) is justified by keeping Mosaic Law. We are only justified by faith.
So then do you think that Romans 3 contradicts Romans 2:13?
In Revelation 14:12, all of those who have faith in Jesus are those who kept God's commands, so only the doers of God's commands have faith in Jesus and are justified by the same faith, which is why Paul said that only doers of the Mosaic Law will be justified. Likewise, in Romans 3:31, our faith does not abolish our need to obey the Mosaic Law, but rather our faith upholds it, yet you seek to abolish rather than uphold it by faith. Paul also denied in Romans 4:1-5 that we can earn our justification as a wage, so there must be reasons other than earning our justification as a wage that our justification requires us to be doers of the Mosaic Law, such as faith and love. Not even Jesus earned his justification by obeying the Mosaic Law because it was never given as a mean of earning our justification as a wage.
According to Acts 21:24-25, the rest of Paul's statements in Acts, and the rest of Paul's writings: The Jews can keep the Mosaic Law as Gentile believers are only commanded to keep the four things in Acts 21:25.
So then do you think that what Paul said in Acts 21:24-25 contradicts what he said in Romans 2:14?
Summmary: You did not give any examples where Paul instructs Gentile believers to keep Mosaic Laws, outside the four things listed in Acts 21:25. Which is exactly my point. So I am not "openly arguing for self-contradictory things".
I listed things like the Ten Commandments, the two greatest commandments, and the things listed in 1 Corinthians 6:9-11 and Galatians 5:19-21, which are all part of the Mosaic Law, so you keep wanting to add parts of the Mosaic Law in accordance with what Paul has instructed while still trying to use Acts 21:24-25 to say that Gentiles should only keep those four things and no other part of the Mosaic Law, which is self-contradictory. Likewise, Titus 3:2-5 lists things that are against the Mosaic Law. Furthermore, Paul also taught Gentiles to repent from sin and the Mosaic Law is how we know what sin is (Romans 3:20).
Peter in Acts 15:6-11 says why the Gentile believers were not insttructed to keep the bulk of the Mosaic Law.
In Acts 15:10-11, verse 11 clarifies that the ruling in verse 10 was in regard to salvation by grace rather than salvation by circumcision. In Acts 15:1, there was a group of men from Judea who were wanting to require Gentiles to become circumcised in order to become saved. In Acts 15:5, they were opposed by a group of Pharisees from among the believers who said that it is necessary to circumcise Gentiles and order them to keep the Law of Moses, but this was not in order result in their salvation.
In Acts 15:6-7, Peter said that Cod chose that by his mouth Gentiles should hear the word of the Gospel and believe. In Matthew 4:15-23, Jesus began his ministry with the Gospel message to repent for the Kingdom of God is at hand, which was a light to the Gentiles, and the Mosaic Law was how his audience knew what sin is, so repenting from our disobedience to it is a central part of the Gospel message, which means that Peter saying that Gentiles were hearing and believing the Gospel is the same as saying that they were repenting and obeying the Mosaic Law. In Acts 15:8-9, Peter said that God who knows the heart, bore witness to them, by giving them the Holy Spirit as he did us, and he made no distinction between them, having cleansed their hearts by faith. Again, in Romans 2:25-29, the Spirit cleansing our hearts refers to a Gentile living in obedience to the Mosaic Law, and Ezekiel 36:26-27, God will take away our hearts of stone, give us hearts of flesh, and send His Spirit to lead us in obedience to the Mosaic Law. Furthermore, Jesus said in Matthew 23:23 that faith is one of the weightier matters of the Mosaic Law, so everything that Peter argued in Acts 15:6-9 leading up to the ruling in verse 10 was in support of the group of Pharisees in Acts 15:5 and against the group from Judea in Acts 15:1.
In addition, in Acts 15:12-18, they quoted prophesies in regard to the Gentiles who are called by God's name being included into Israel, which again is in support of obeying the Law of Moses, so no one there was arguing that Gentiles shouldn't obey the Law of Moses, but rather they were making a ruling about the means of becoming saved by grace rather than by circumcision. So once they ruled in favor of the group in Acts 15:5 that Gentiles should become circumcised and ordered to obey the Law of Moses, it then became an issue that it would be overwhelming for new believers to order them to keep all of the Law of Moses, so in order to avoid making it too difficult for them, they started them off with four things with the expectation that they would continue to learn about how to obey Moses over time by hearing him taught every Sabbath in the synagogue (Acts 15:19-21).