Lon Milo Duquette the Thelemist occultist? I imagine he’d have incentives for taking maximalist interpretations, even if it involves taking leaps of faith. And doesn’t most of the “evidence” of the Illuminati existing beyond Weishaupt’s group come from hysterical anti-Masonic conspiracy theorists like Abbé Barruel (who blamed the horrors of the French Revolution on Masonry and Illuminism, which he conflated into a Satanic plot), and from other anti-Masonic conspiracy theorists who drew on his work?
Not that there weren’t groups claiming descent from the Illuminati, but along the same lines, for a long time you could join the Rosicrucians by sending a check to a PO box advertised in a magazine.