dpr - You really need to check out the evidence for Nero being the reigning emperor at the time John drafted Revelation.
Solid evidence is there in the ancient Syriac Peshitta version's title page for Revelation. Have you seen this? I quote: " The revelation which was upon the holy John the Evangelist from God when he was on the island of Patmos where he was thrown by the emperor NERO." No ambiguity there at all.
Irenaeus does not stipulate in his famous quote as to whether John was seen or the apocalyptic vision was seen in Domitian's reign. The scribe who translated Irenaeus into Latin inserted his own preference when he interpreted what was seen. The original Greek that Irenaeus wrote this statement in has no word for what was seen - the referrent has to be assumed. And every historian quoting Irenaeus since then has made the same assumption, including yourself.
In addition, since Nero's birth name was "Lucius Domitius Ahenobarbus", there have been historians, (Severus, Orosius, etc.) who have mistakenly confused Nero's "Domitius" or "Domitianou" with the later "Titus Flavius Domitianus", son of Vespasian. The resulting confusion hs been passed down to later generations and has continued to muddy the waters of Revelation's study today.
It is much safer to rely on internal testimony for the dating of this book. And there is ample internal evidence and cross-referencing with the rest of scripture to show that Revelation was written in late AD 59 to early AD 60. I have attempted to lay out the evidence for this on this website and others, for those who are willing to devote the time necessary to seriously study this issue.
Just as an aside to your Zechariah 6 reference, the BRANCH in Zech. 6 is speaking of Jesus (or Joshua) the son of Josedec the high priest, who became the crowned high priest in the rebuilt temple of Zerubbabel after the post-exilic return. This temple prophesied by Ezekiel was already built long ago under Zerubbabel's hands, and was eventually renovated extensively by Herod. Here are the LXX verses in Jeremiah 23:5-6 that foretell how Josedec, (Jesus / Joshua's father), would also be designated as the BRANCH. "Behold the days come, saith the Lord, when I will raise up to David a righteous branch, and a king shall reign and understand, and shall execute judgment and righteousness on the earth. In his days both Juda shall be saved, and Israel shall dwell securely: and this is his name, which the Lord shall call him, JOSEDEC among the prophets." Jesus / Joshua shared in his father's name of THE BRANCH, and the post-exilic remnant that returned did finally come to enjoy periods of peace and prosperity under the Medo-Persians, led by Jesus / Joshua's rule as high priest.