Was James Anti-Paul?
Matthew is much more of a Judaizing character than James is.
I don't see James in opposition to Paul to the extent that Matthew is. Paul and James can be much more easily harmonized than Paul and Matthew. Paul preaches good works through faith, but not in a legalistic way. Paul is not anti-good works, but rather anti-legalism.
James 2:21-24 (RSV)
<21> Was not Abraham our father justified by works, when he offered his son Isaac upon the altar? <22> You see that faith was active along with his works, and faith was completed by works, <23> and the scripture was fulfilled which says, "Abraham believed God, and it was reckoned to him as righteousness"; and he was called the friend of God. <24> You see that a man is justified by works and not by faith alone.
Not faith without works (no such thing)
Not works without faith (legalism)
James' reference to works is not an explicit reference to the Law, but to Abraham offering his son.
James emphasized faith, he was into faith healing…
James 5:14-15 (RSV)
<14> Is any among you sick? Let him call for the elders of the church, and let them pray over him, anointing him with oil in the name of the Lord; <15> and the prayer of faith will save the sick man, and the Lord will raise him up; and if he has committed sins, he will be forgiven.
Also, James doesn't identify pure religion to be adherence to the complete Law of Moses, but rather to look after orphans and widows in their distress and keeping oneself from being polluted by the world. If James were a Judaizer, he would have made explicit reference to the Law.
James 1:27 (REV)
<27> Religion that is pure and undefiled before God and the Father is this: to visit orphans and widows in their affliction, and to keep oneself unstained from the world.
Judaizers try to claim that James supports their views, but it is all conjecture. His statements are more aligned with Paul than Judaizers.
Matthew is totally a different story. See Matthew is a Judaizing document: https://issueswithmatthew.com/matthew-judaizing/