IMO the Pharisees were not adamant about the necessity of strictly following YHVH's written Law. They were, however, adamant about the need to follow their so-called "oral Law" - that is, their traditions about YHVH's Written Law. In essence, the Pharisees were lax about following YHVH's Law. (The Sadducees were, in actuality, the group that was strict about YHVH's Written Law, and rejected the Pharisees' "oral law" traditions).
I see, in the same way, Paul requiring his disciples to follow his traditions (Col 2:8, 2Th 3:6, Gal 1:6-12, etc.) regarding the Law and Jesus, and he was quite lax about the Law. So, in that regard, I see Paul as clearly a Pharisee.
Colossians 2:6-9
6 As you therefore have received Christ Jesus the Lord, so walk in Him, 7 rooted and built up in Him and established in the faith, as you have been taught, abounding in it with thanksgiving.
8 Beware lest anyone cheat you through philosophy and empty deceit, according to the tradition of men, according to the basic principles of the world, and not according to Christ. 9 For in Him dwells all the fullness of the Godhead bodily; 10 and you are complete in Him, who is the head of all principality and power.
2 Thessalonians 3:6-12
6 But we command you, brethren, in the name of our Lord Jesus Christ, that you withdraw from every brother who walks disorderly and not according to the tradition which he received from us. 7 For you yourselves know how you ought to follow us, for we were not disorderly among you; 8 nor did we eat anyones bread free of charge, but worked with labor and toil night and day, that we might not be a burden to any of you, 9 not because we do not have authority, but to make ourselves an example of how you should follow us.
10 For even when we were with you, we commanded you this: If anyone will not work, neither shall he eat. 11 For we hear that there are some who walk among you in a disorderly manner, not working at all, but are busybodies. 12 Now those who are such we command and exhort through our Lord Jesus Christ that they work in quietness and eat their own bread.
Galatians 1:6-16
6 I marvel that you are turning away so soon from Him who called you in the grace of Christ, to a different gospel, 7 which is not another; but there are some who trouble you and want to pervert the gospel of Christ. 8 But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed. 9 As we have said before, so now I say again, if anyone preaches any other gospel to you than what you have received, let him be accursed.
10 For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ.
11 But I make known to you, brethren, that the gospel which was preached by me is not according to man. 12 For I neither received it from man, nor was I taught
it, but
it came through the revelation of Jesus Christ.
13 For you have heard of my former conduct in Judaism, how I persecuted the church of God beyond measure and
tried to destroy it. 14 And I advanced in Judaism beyond many of my contemporaries in my own nation, being more exceedingly zealous for the traditions of my fathers.
15 But when it pleased God, who separated me from my mothers womb and called
me through His grace, 16 to reveal His Son in me, that I might preach Him among the Gentiles
I have included the verses you are referencing above, can you tell me what exactly bothers you about Paul and his writings?