I'd say our assessments of James aren't that far off, but I don't believe James is simply speaking of evidence.
James 2:18 - But someone will say, “You have faith, and I have works.” Show me your faith without your works, and I will
show you my faith by my works. We
show that our faith is genuine by our works.
In James 2:14, we read of one who
says/claims he has faith but has
no works (to evidence his claim). That is not genuine faith, but a
bare profession of faith. So when James asks, "Can
that faith save him?" he is saying nothing against genuine faith, but only against an
empty profession of faith/dead faith. So James
does not teach that we are saved "by" works. His concern is to
show the reality of the faith professed by the individual (James 2:18) and demonstrate that the faith claimed (James 2:14) by the individual is genuine.
Especially because he states that the works complete/perfect the faith and besides rhetorically challenging to show faith vs show works (which instead of being so James can know they have faith seems to be intended to ridicule the one saying "he has works, I have faith" by demonstrating that there is no substance to the claim.)
In James 2:22, "faith made perfect" or "complete by works" means bring to maturity, carry to the end, to complete like love in 1 John 4:18. It does not mean that Abraham was finally saved based on merits of his works after he offered up Isaac on the altar in Genesis 22. When Abraham performed the good work in Genesis 22; he
fulfilled the expectations created by the pronouncement of his faith in Genesis 15:6.
The idea in James is that faith is more than an agreement with statements of facts. It's not simply accepting that Jesus died and rose again but living the life that such a truth demands.
In James 2:19, we see that the demons believe "mental assent" that "there is one God," but they
do not believe in/have faith in/trust in/reliance in Jesus Christ for salvation. In other words, they
do not believe in the Lord Jesus Christ (Acts 16:31) and are not saved. Their trust and reliance is in Satan, as demonstrated by their rebellion in heaven and continuous evil works.
It's not enough to merely believe "mental assent" that the death, burial and resurrection of Christ "happened." We must also
trust in the death, burial and resurrection of Christ as the ALL-sufficient means of our salvation. That is what it means to
believe the gospel. (Romans 1:16; 1 Corinthians 15:1-4) All genuine believers are fruitful, yet not all are equally fruitful. (Matthew 13:23)