...so because Tony Bushby has "made stuff up", then Revelation really was written by John the Apostle on the Island of Patmos, and it really is about Jesus of Nazareth, and we can go back to our Orthodox Box... is that correct?
No, are you trying to posit a false dilemma here? It's either Bushby's BS or the traditional, devotional account? What about critical scholarship? There has been a lot of research on the composition of Revelation over the years, and I have always been an advocate of higher criticism. I don't like the intimation that if I am critical of a peddler of pseudohistory like Bushby, then I must be an apologist. I got that from Shawn10538 when I pointed out the dishonesty in Zeitgeist and I got that from skyman when I did the same wrt the "Kolbrin Bible". It's stupid and annoying.
If Revelation and the Gospels were written around the same time, why does the Revelation contain so much Old Testament symbolism? If it didn't have "Jesus" in there, I would look at it and think it belongs at the end of the OT, not the NT.
I don't understand your question because the gospels are densely intertextual with the OT as well. And this was very typical with apocalyptic works like 1 Enoch and Revelation, which equally are dependent on OT texts, but since Revelation is probably dependent on 1 Enoch (just as the gospels are), Revelation is definitely later. Revelation belongs with other contemporaneous apocalypses and not with the non-apocalyptic literature of the OT, although it also imitates the genre of prophecy. Many scholars do believe that some units within Revelation have a non-Christian Jewish origin, and it has been pointed out that the reference to Jesus in these units is redactional (see Aune's commentary). This is the sort of thing you'd find in critical scholarship, not Christian apologetics.
As for the book's acceptance into the canon, it was controversial because it is a Gnostic writing
Revelation is hardly gnostic, LOL. The gospel of John is much closer to gnostic ideas than Revelation, which is one reason why people in the early Church doubted that Revelation was written by Apostle John because the language and conception is so different from John. The realized eschatology in John (which is far more cognate to what is found in gnostic literature) contrasts with the imminence and chiliasm of Revelation. It is in the shift away from the kind of eschatology in Revelation that you find more overt gnostic ideas. So the Gospel of Thomas in its present form is quasi-gnostic, but as April DeConick shows, many of these logia originally had a more imminent eschatology that later was recast in more realized terms. Revelation represents an eschatology rather akin to Matthew that still expects very soon the events concluding the eschaton. It has no "typical" gnostic ideas, like the pursuit of self-knowledge for spiritual liberation from flesh, or a demiurgical view of creation, or the procession of aeons from the true God, etc. The earliest opponent of chiliasm was in fact the gnostic Marcion.
It was controversial because it was chiliast and chiliasm was a big no-no after the third century AD. Just look at Eusebius' criticisms of Papias.