If you want the Snow Crash version of Da Vinci Code, then you might like The Illuminatus Trilogy. Robert Anton Wilson is something else. Umberto Eco's book Foucault's Pendulum is a slightly different vibe, but very entertaining read.
https://en.wikipedia.org/wiki/The_Holy_Blood_and_the_Holy_Gr...
I remember reading it in the 90s and being very put off by the insanity and lack of logic. As it later turned out: The conspiracy theory of HBHG and DVC was in the end invented by a French document forger who in his own forgery seemed to be the last merovingian king/descendent of Christ:
It's an interesting book, and it does engage, but it is also quite the trip.
This is sometimes called conspiracy fiction, and one cool thing about it is that the form as such doesn’t strictly imply or require a specific genre, so it works just as well with any or all of sci-fi / noir / historical fiction. Apparently renowned author Dan brown can easily understand that mixing with actual treasure hunt instead of some kind of forbidden knowledge is part of the formula for giving it the most popular appeal.