Paul was trying to destroy the church.
Paul was saved and was a testimony to the worst of sinners being able to be saved too.
1 Timothy 1:16 But for that very reason I was shown mercy so that in me, the worst of sinners, Christ Jesus might display his immense patience as an example for those who would believe in him and receive eternal life.
As Clete might also say, on a good day, lol, it just might be not so much that you are consciously up to no good, rather that thus far, you have not been persuaded to seeing, nor have been able to see, where we are actually coming from on these issues.
For example, while valid, this thing you often assert about Paul having been referring to circumcision and the Law's various other rituals, whenever he writes of "not of works" nevertheless, his writings also repeatedly show that that is only the half of what he writes on that.
The other half being what he also often writes of those practices the Gentiles also had within their own, Gentile world made up concept of various gods and of the need to do works to appease them.
That is an aspect also described in the OT, as well.
A very simple...example of this aspect of works also addressed at the Cross...
Habakkuk 2:18 What profiteth the graven image that the maker thereof hath graven it; the molten image, and a teacher of lies, that the maker of his work trusteth therein, to make dumb idols? 2:19 Woe unto him that saith to the wood, Awake; to the dumb stone, Arise, it shall teach! Behold, it is laid over with gold and silver, and there is no breath at all in the midst of it.
Matthew 6:7 But when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking.
1 Corinthians 12:2 Ye know that ye were Gentiles, carried away unto these dumb idols, even as ye were led.
There that was, in Paul's day - those works that Gentiles engaged in, in the service of their made up, pagan gods.
Here that is, again...
Galatians 4:8 Howbeit then, when ye knew not God, ye did service unto them which by nature are no gods. 4:9 But now, after that ye have known God, or rather are known of God, how turn ye again to the weak and beggarly elements, whereunto ye desire again to be in bondage? 4:10 Ye observe days, and months, and times, and years.
The foolish Galatians ended up going from those works in the service of their pagan gods that the Gentiles themselves had come up with, Romans 1: 21-23, to those works in the service of God under the Law that Israel had been given, Romans 9: 4,5 - both ordinances actually against man - that the Cross of Christ had put away, by the sacrifice of Himself, Eph. 2; Col. 2.
Your argument that Paul is only referring to those works under the Law, needs reevaluating.
That is what all this boils down to, things (plural) still in the way of your seeing what MADs are forever rightly going on about, regarding works during this Mystery GRACE Age.
Acts 17: 11, 12