What we know of the Illuminati likely came from whistleblowers of those inside. How would we expect to have an unbiased view from those actively participant? So of course most of our information came from dissidents of the group.
What we know is of their accounts. Some of which seem speculative at best, far-fetched at most, and having some fantasy. Critics claim that their stories don’t add up, their timelines are off, and their facts cannot be substantiated.
But we know the Illuminati provide their own cover-up campaigns, shaping culture, altering sources, rewriting history, suppressing information, making rabbit trails stop, witnesses vanishing, and no traces of proof.