You ask as to who this Revelation (the last book of the Christian Greek scriptures) is given. Then you make the comment that this Apocalypse of Yeshua the Messiah is given to Yeshua indirectly via an Angel or Messenger. But if that is so, then the answer to your question must be that this Revelation is given by an angel to the risen Christ Jesus! That is not what the text states. Let me quote from the A.V.
"The Revelation of Jesus Christ, which God gave unto him, to show unto
his servants things which must shortly come to pass; and he sent and
signified it by his angel unto his servant John; who bare record of
the word of God, and of the testimony of Jesus Christ, and of all
things that he saw". (Revelation 1:1,2)
The Revelation is given by God, to Jesus Christ. It could not be clearer. Then Jesus Christ sends his angel to signify this Revelation to his servant John. From the start, and intermittently thereafter, John sees visions of Jesus Christ in his risen glory, and hears his Lord speak directly to him. He also sees visions and hears explanations via this angel. The whole record is a prophecy of the activity of various angels from the time of John till the Day of Resurrection and Judgment. Just as the book of Acts could rightly be considered The Acts of the Holy Spirit, so the book of Revelation could rightly be considered The Acts of Angels.
Now let me quote the significance of this in the book referred to below:
"Observe that the book is a revelation of Jesus Christ. If so, it
discloses that about him not unveiled before, but now revealed in this
book. The Revelation is what John actually saw. In consequence he
described the vision in writing... Note that it was not given directly
by Jesus Christ. Rather, 'he sent and signified it by his angel.' This
is of the greatest importance.
"Again, notice that by his angel the revelation was sent and
signified to the servant of Jesus Christ called John, that by his pen
it was to be sent to all the people of God: 'to show unto his servants
things which must shortly come to pass', Rev. 1:1.
Given of God to Jesus Christ, sent by the angel of Jesus Christ,
signified to the apostolic ministry, by this means it was to be shown
to all those who serve God, and Jesus Christ his Son.
"...There is no question to the spiritual but that this refers to the
apostle John, the writer of the fourth gospel, and of three further
epistles. This is the more remarkable in view of the long obscurity of
John between his initial prominence in the gospels, and his
conspicuous reappearance at the very end.
"In the gospels 'Jesus saith unto him' - that is, to Peter - 'If I
will that he' - John - 'tarry till I come, what is that to thee?',
John 21:22. 'Then went this saying abroad among the brethren, that
that disciple should not die: yet Jesus said not unto him, He shall
not die; but, If I will that he tarry till I come, what is that to
thee?' John 21:23.
"At that time John was about thirty to thirty-five years of age. From
that moment until the writing of the fourth gospel and the three
epistles, but above all until the setting down of this book, John
tarried. Then Jesus came, appearing by his angel to give the
Revelation of Jesus Christ to his slave John. John tarried: but the
reason was that he was constrained by a spiritual discipline virtually
unknown in church history and certainly unknown at the present time.
"...John had survived the first generation, and seen the passing away
of the second generation as that in turn aged and departed. John had
endured the persecutions of Nero. He had seen the end of the apostles,
Paul included, long, long ago. But now storm clouds began to gather
again. Under the Roman Emperor Dominitan the fires of persecution were
rekindled.
"The Dominitan persecutions raged from the year 81 to 96. During this
period the last apostle, John, was banished to the remote Island of
Patmos. This was about the year 95. This approximated to the great age
of the apostle. It was also about the time in which at long last there
came the conclusion to John's seemingly endless 'tarrying'.
"Finally, in the Spirit, and by his angel, the Lord came for John, and
came that he might render the last, the great, the consummate witness
of the new testament, till time should be no more (Rev. 10:6).
"It was for this, the Revelation of Jesus Christ - above and beyond
the fourth gospel and the three epistles - that the slave of Jesus
Christ had been kept for longer than might be considered endurable or
even possible. But by the grace of the Spirit he had been kept; by the
grace of Christ he had endured; and by the grace of God he had
submitted. Now at length he was called to render the most momentous,
the most overwhelming testimony of all the sixty-six books of the Holy
Bible, with which the whole was to be brought to its fitting
conclusion.
"Although the Revelation is that of Jesus Christ, who, under various
figurative symbols and graphic descriptions, appears frequently in the
narrative, as does his own speech, nevertheless this revelation was
not given directly from the Lord to John. 'He sent and signified it
by his angel unto his servant John'." (The Revelation of Jesus Christ, pages 1 to 4, John Metcalfe)
I trust that all your queries are answered by this lengthy quote.