Gal 1:17 nor did I go up to Jerusalem to those who were apostles before me, but I went away into Arabia; and again I returned to Damascus....
b) According to 'Acts', first version:
Act 9:3 Now as he journeyed he approached Damascus, and suddenly a light from heaven flashed about him.
Act 9:4 And he fell to the ground and heard a voice saying to him, "Saul, Saul, why do you persecute me?"
Act 9:5 And he said, "Who are you, Lord?" And he said, "I am Jesus, whom you are persecuting;
Act 9:6 but rise and enter the city, and you will be told what you are to do."
Act 9:7 The men who were traveling with him stood speechless, hearing the voice but seeing no one.
Act 9:8 Saul arose from the ground; and when his eyes were opened, he could see nothing; so they led him by the hand and brought him into Damascus.
c) According to 'Acts', second version:
Act 22:6 "As I made my journey and drew near to Damascus, about noon a great light from heaven suddenly shone about me.
Act 22:7 And I fell to the ground and heard a voice saying to me, 'Saul, Saul, why do you persecute me?'
Act 22:8 And I answered, 'Who are you, Lord?' And he said to me, 'I am Jesus of Nazareth whom you are persecuting.'
Act 22:9 Now those who were with me saw the light but did not hear the voice of the one who was speaking to me.
Act 22:10 And I said, 'What shall I do, Lord?' And the Lord said to me, 'Rise, and go into Damascus, and there you will be told all that is appointed for you to do.'
Act 22:11 And when I could not see because of the brightness of that light, I was led by the hand by those who were with me, and came into Damascus.
d) According to 'Acts', third version:
Act 26:12 "Thus I journeyed to Damascus with the authority and commission of the chief priests.
Act 26:13 At midday, O king, I saw on the way a light from heaven, brighter than the sun, shining round me and those who journeyed with me.
Act 26:14 And when we had all fallen to the ground, I heard a voice saying to me in the Hebrew language, 'Saul, Saul, why do you persecute me? It hurts you to kick against the goads.'
Act 26:15 And I said, 'Who are you, Lord?' And the Lord said, 'I am Jesus whom you are persecuting.
Act 26:16 But rise and stand upon your feet; for I have appeared to you for this purpose, to appoint you to serve and bear witness to the things in which you have seen me and to those in which I will appear to you,
Act 26:17 delivering you from the people and from the Gentiles--to whom I send you
Act 26:18 to open their eyes, that they may turn from darkness to light and from the power of Satan to God, that they may receive forgiveness of sins and a place among those who are sanctified by faith in me.'
Comment: According to Paul, his first revelation came from God. According to 'Acts', Paul had that revelation from the heavenly Jesus, not God, as known through three different versions of the same alleged event.
There is a conflict between the two first versions: in one, Paul's companions hear the voice; in the other, they do not hear it!
And only in the third version, Jesus is sending Paul to the Gentiles!
2) Paul's escape from Damascus:
a) According to Paul:
2Cr 11:32 At Damascus, the ethnarch under King Ar'etas guarded the city of Damascusin order to seize me,
2Cr 11:33 but I was let down in a basket through a window in the wall, and escaped his hands.
b) According to 'Acts':
Act 9:22 But Saul increased all the more in strength, and confounded the Jews who lived in Damascus by proving that Jesus was the Christ.
Act 9:23 When many days had passed, the Jews plotted to kill him,
Act 9:24 but their plot became known to Saul. They were watching the gates day and night, to kill him;
Act 9:25 but his disciples took him by night and let him down over the wall, lowering him in a basket.
Comment: According to Paul, the ethnarch of king Aretas is after him, but not to kill Paul, just to make an arrest. However, in 'Acts', the Jews are watching the gates and want to kill Paul (the Jews are the arch enemy of Paul all over 'Acts').
3) Paul's first visit to Jerusalem after his conversion:
a) According to Paul:
Gal 1:18 Then after three years I went up to Jerusalem to visit Cephas, and remained with him fifteen days.
Gal 1:19 But I saw none of the other apostles except James the Lord's brother.
Gal 1:20 (In what I am writing to you, before God, I do not lie!)
b) According to 'Acts':
Act 9:26 And when he had come to Jerusalem he attempted to join the disciples; and they were all afraid of him, for they did not believe that he was a disciple.
Act 9:27 But Barnabas took him, and brought him to the apostles, and declared to them how on the road he had seen the Lord, who spoke to him, and how at Damascus he had preached boldly in the name of Jesus.
Act 9:28 So he went in and out among them at Jerusalem,
Act 9:29 preaching boldly in the name of the Lord. And he spoke and disputed against the Hellenists; but they were seeking to kill him.
Act 9:30 And when the brethren knew it, they brought him down to Caesare'a, and sent him off to Tarsus (Cilicia).
Comment: Paul said he was unable to see the disciples/apostles (except two) but 'Acts' has Paul mingling with all of them in Jerusalem.
"Luke" wanted Paul to have good relation with the church of Jerusalem and apostles before him.
4) Paul at the council of Jerusalem:
a) According to Paul:
Gal 2:1 Then after fourteen years I went up again to Jerusalem with Barnabas, taking Titus along with me.
Gal 2:2 I went up by revelation; and I laid before them (but privately before those who were of repute) the gospel which I preach among the Gentiles, lest somehow I should be running or had run in vain.
Gal 2:3 But even Titus, who was with me, was not compelled to be circumcised, though he was a Greek.
Gal 2:4 But because of false brethren secretly brought in, who slipped in to spy out our freedom which we have in Christ Jesus, that they might bring us into bondage--
Gal 2:5 to them we did not yield submission even for a moment, that the truth of the gospel might be preserved for you.
Gal 2:6 And from those who were reputed to be something (what they were makes no difference to me; God shows no partiality)--those, I say, who were of repute added nothing to me;
Gal 2:7 but on the contrary, ...
Gal 2:9 James and Cephas and John, who were reputed to be pillars, gave to me and Barnabas the right hand of fellowship, that we should go to the Gentiles and they to the circumcised;
Gal 2:10 only they would have us remember the poor, which very thing I was eager to do.
b) According to 'Acts':
Act 15:1 But some men came down from Judea and were teaching the brethren, "Unless you are circumcised according to the custom of Moses, you cannot be saved."
Act 15:2 And when Paul and Barnabas had no small dissension and debate with them, Paul and Barnabas and some of the others were appointed to go up to Jerusalem to the apostles and the elders about this question.
Act 15:3 So, being sent on their way by the church, they passed through both Phoeni'cia and Sama'ria, reporting the conversion of the Gentiles, and they gave great joy to all the brethren.
Act 15:4 When they came to Jerusalem, they were welcomed by the church and the apostles and the elders, and they declared all that God had done with them.
Act 15:5 But some believers who belonged to the party of the Pharisees rose up, and said, "It is necessary to circumcise them, and to charge them to keep the law of Moses."
Act 15:6 The apostles and the elders were gathered together to consider this matter.
Act 15:7 And after there had been much debate, Peter rose and said to them, "Brethren, you know that in the early days God made choice among you, that by my mouth the Gentiles should hear the word of the gospel and believe.
Act 15:8 And God who knows the heart bore witness to them, giving them the Holy Spirit just as he did to us;
Act 15:9 and he made no distinction between us and them, but cleansed their hearts by faith.
Act 15:10 Now therefore why do you make trial of God by putting a yoke upon the neck of the disciples which neither our fathers nor we have been able to bear?
Act 15:11 But we believe that we shall be saved through the grace of the Lord Jesus, just as they will."
Act 15:12 And all the assembly kept silence; and they listened to Barnabas and Paul as they related what signs and wonders God had done through them among the Gentiles.
Comment: According to Paul, it is clear him and Barnabas met with only a few pillars of the church of Jerusalem. But according to 'Acts', the twosome & others from Antioch attended the council with a whole assembly of apostles, elders and believers.
Again, "Luke" wanted Paul to be in excellent relation with the whole church of Jerusalem, fully approving his actions (rather lack of: no circumcision) towards the Gentiles. And Peter's alleged speech would make Paul very happy!
Overall conclusion for point 3.:
With so much differences (sometimes conflict) between the different accounts of the same events, it is very unlikely "Luke" knew about the Pauline epistles. There is no way "Luke" could have afforded to make the drastic changes & embellishments if Paul's letters were readily available in the community (probable exception: Philippians).
"This is not to say that Acts is totally unhistorical but to observe that it is less helpful in the historical reconstruction of Christian beginnings than previously assumed."
That's an admission 'Acts' is partially historical.
And I find myself basically agreeing with scholar James Tabor on these comments on pages 229-230 of "Paul and Jesus " (2012), but with some reservations: