Scholars commonly view the Book of Revelation as a political allegory. The real target is Rome, but John must use code language to protect the recipients. If he were pen an open indictment of the Roman regime, his recipients would be persecuted as enemies of the state.
I think there's some truth to this. A classic example is Dostoevsky's the Grand Inquisitor in the Brothers Karamazov. Although he's a Roman Catholic figure, Dostoevsky's real target is the Russian Orthodox Church. But he couldn't get away with attacking that directly, so he uses the Grand Inquisitor as a stand-in.
However, the logic of the allegorical interpretation doesn't automatically select for a 1C setting. Suppose, for the sake of argument, that God gave John a preview of the rise of Stalinism or Nazism. That would need to be coded for the same reason that targeting the Roman regime would need to be coded. It gives the recipients plausible deniability.
If a book of the Bible were to directly attack Stalinism or Nazism, that would lead those regimes to ban the Bible. Confiscate copies. Mere ownership of Scripture would be a capital offense. If the regime could recognize itself in the description, it would treat that as seditious literature.
So the fact that Revelation is, to some degree, a political allegory, doesn't select for preterism. For that's equally consistent with futurism. Or "modified idealism."
I think John's original recipients were able to discerned a veiled attack on Rome. But I also think the cryptic symbols can just as well apply to later events. It deals with certain kinds of figures, institutions, and events.