The "mark of the beast", for example (666), is the result of an ancient Jewish mystic numerology game where they assigned each letter a numeric value to speak about people in code. 666 means Nero.

You, my friend, are ill-informed. The idea of the antichrist has deep and complex origins that developed over centuries, blending Jewish apocalyptic expectations, early Christian theology, and later medieval interpretation.

John 2:18 — “Children, it is the last hour; and as you have heard that Antichrist is coming, so now many antichrists have come.”

1 John 4:3 — “This is the spirit of the Antichrist, which you heard was coming and now is in the world already.”

https://en.wikipedia.org/wiki/Antichrist

It's a later addition, does not refer to one individual only and is said to

... may have been generated by the frustration of Jews subject to often-capricious Seleucid or Roman rule, who found the nebulous Jewish idea of a Satan who is more of an opposing angel of God in the heavenly court insufficiently humanised and personalised to be a satisfactory incarnation of evil and threat same source.

There is quite a lot of nuance here. You can’t just keyword search.

Even if some are rooted in some real person, the stories about them etc. cannot be considered accurate historical accounts.

If you want scholarly, informed, resources that aren't an ignorant billionaire talking out of his ass, I can provide those. If you aren't interested, kindly stop replying to this thread.

That's a very strange thing to say, unless the sarcasm meter was missing. If Thiel's views are only for the cognoscenti, then I think we have bigger problems to talk about.