I have the most useless degrees in the world, Bachelors in Religious Studies (Studied Hebraic, Islamic, Mormon, and Hindu thought) and a Masters in Christian thought.
So, I may have some education and standing to offer an account.
From my understanding of Revelation, the writer, John the Seer, is speaking directly to Christians in the first century CE, he is warning them that their persecution will continue but ultimately, Jesus will return and make all things new (Revelation 21.5).
The 666 is not to be understood as the number between 665 and 667. Nope, it's actually 600, 60, and 6 in the Greek. It's spelling out a name: Nero (either referring to Nero himself or Domitian known as the 2nd Nero). Revelation found in other translations in other languages spell this out as well since the number in those manuscripts isn't 600, 60, and 6, but a different number that correlates with the letters NERO in their alphabet.
So, the "anti Christ" that John the Seer was referring to is long past dead. Revelation was written for the Christians in first century CE. Whether you believe it speaks to Christ-followers today or not, that's up to you.