Well, you will have to take that up with whoever added titles to the books of the NT, because their authorship is highly suspect. The oldest copies (actually shreds or, more politically correct "fragments") do not show titles, but that's another story.
Anyway, as far as those who consider every dot and line in the current copies to be the unquestioned word of God, the Book of Revelation of the NΤ bears the title, in Greek: ΑΠΟΚΑΛΥΨΙΣ ΙΩΑΝΝΟΥ (the Revelation of John).
The Greek word apokalypsis (revelation) means "lifting of the veil." So this lifting of the veil pertains to John; we can say thus that John had [experienced] a revelation from God! Christ, being God, never had a revelation (i.e. "lifting of the veil"); it is He who reveals, not to one to whom it is revealed.
The problem is you are reading the Bible in English, where foreign words give it a rich vocabulary but are used as empty labels without inherent meaning. English-readers of the Bible, however, insist that the HS prohibits them from reading the Word of God in error. I am not convinced.
You can continue to claim that the title is wrong as long as you remember that once you subject to doubt one iota in the Bible, you might as well subject everything in it to doubt.
Speaking of the Book of Revelation, it is no longer regarded as unquestionably written by John the Apostle. But, be it as it may, it was written one way or another by an End-if-Times Jewish believer with advanced theology and exceptional literacy in Greek, for he says "the things which have to happen "in speed" [Greek εν ταχει], or "soon" [NIV, NAB], as some translate, or "shortly come to pass" [KVJ].
This tells us that even after the HS was sent to the Apostles, they continued to live and believe in the imminent End-of-Times and preach that the Kingdom of God is at hand, as they were commissioned to do (to the Jews only, cf. Mat 10:5).
Certainly, +Paul was an apocalyptic Jew, and certainly +Peter was too despite the fact that Christ never said it was "soon," but He did say that it would be "before this generating comes to pass," and that "there are some of those who are standing here who will not taste death until they see the Son of Man coming in His kingdom."[Mat 16:28, Mar 9:1, Luk 9:27]. / NB: John 8:52 says something similar but it sounds more like "keeping the law" than just having faith/
Various bible scholars, ever since the 2nd century had to struggle to "explain" why the End-of-Times hasn't happened yet when it was supposed to happen "in speed" as the Bible says, but that's another thread. :)
Suffice it to say that the realization has slowly faded away and was neatly tucked under the carpets by the Church so as not to be something we think about very often, and very possibly this may be why the Book of Revelation is never read in the Orthodox Church.
It's one of those "depends what you mean by 'is' issues."
Since my own revelation(s) from God tends to enhance or complete the Revelation of Jesus(bible book) given to John as a revelation.. maybe understanding that book is on a need to know basis.. My understanding is that any revelation is limited according to the ability to grasp it.. Example: I have had several "revelations" of sacrifice over the years each deeper in content and depth.. same with other issues..
What "heaven" and "hell" are, are also the same.. What they are or could be is limited to the "observers" ability to observe.. A "lifting of the veil" really.. Amazing that a human upon a revelation can "DECLARE" that they finally understand something.. When their understanding has just reached another level but no means they fully understand..
And MORE if a "christian" has never had a "vision/revelation" I wonder if they understand much at all..
There is a 240 year difference between the Jewish calendar and the Christian calendar - but if the Christian calendar is right, then Christ's millenium - the 1,000 year Sabbath - is due to start any time now, but only the Father knows when.