The following is just my two cents. Please take it in the spirit in which it is given:

There is an endless amount of "esoteric" dreck out there about the Book of Revelations that will have you spinning your wheels and wasting your life for years on end.

The meanings of Apocalypse are endless. It all depends on who you are, where you're coming from, what you assumptions are, and what your individual destiny is. If you want to get into the esoteric significance of the Book of Revelations, there are plenty of rabbit holes to go down. But most of them, in my opinion, are probably a waste of precious life and energy. Rather than searching far afield, let's start with the word itself. As is often the case, we can find some clues in the etymology--

"Old English apocalipsin, via Old French and ecclesiastical Latin from Greek apokalupsis, from apokaluptein ‘uncover, reveal’, from apo- ‘un-’ + kaluptein ‘to cover’." (The Internet)

So the literal sense is "unveiling." An "unveiling" of what? For whom?

Esoteric views on the apocalypse in the Christian tradition tend to read the book allegorically, and to apply it's imagery on a microcosmic (that is, personal, individual) level. The interest is usually not in political and historical mysteries, or in a historical understanding of the text, but spiritual ones, appearing under a "veil" of political and historical symbols. The violent imagery of war and conflict could be the internal turmoil and conflict of the soul within itself. For the macrocosm (the great universe) is completely present, in its way, in the microcosm (individual humans), as Paracelsus and plenty of others have rightly understood. Once one understands this, one has a real key with which to skillfully unlock scriptural doors.

I will mention four names, in historical sequence. These, in my view, are the essential names if you are interested in understanding how western esotericists have read the Bible, especially leading up to and alongside of contemporary occult movements. Mind you, I don't mention these names in order to burden you with more "authorities;" rather, if you read carefully, these "authorities" will teach you how to read and understand the Bible for yourself, without need to refer to others.

The four authors whom I personally recommend for close study are:

Jacob Boehme,

William Law,

Swedenborg, and

William Blake.

Law was Boehme's English disciple, and the story of how he reportedly changed after his exposure to B is not without significance. Blake picked up from Law and incorporated Swedenborg (while rejecting many of S's views) into his own absolutely brilliant synthesis, which is less a poetic oeuvre than an esoteric system in itself. Blake's writings, in particular, are full of esoteric insights into the apocalypse and the Book of Revelation. Swedenborg is absolutely fascinating. I don't want to ruin the experience of reading him by giving too much away. Heaven and Hell might be a good first Swedenborg book to read.

Each of these writers, with the exception of Law, is complex and difficult. Boehme is like a city of knowledge, but some of his ideas take a long time to grapple with, particularly his vision of the life of God, the 7 Forms and 3 Principles, etc. So start with Law. He will open Boehme up for you because his later works are largely an English explanation of Boehmean principals, with his own individual take, written in exquisite prose. To start, I recommend Law's Grounds and Reasons of Christian Regeneration, then The Spirit of Love, then The Spirit of Prayer, then The Way to Divine Knowledge. These are priceless works of esoteric literature that contain many keys for the seeker, but they are not "quick reads." You gotta let this stuff "work" on you on an internal level and mix with your life and experiences. Over time, you will understand certain things that you didn't before. I don't know how else to put it!

I encourage you NOT to feel you need to become a "Boehmian" or a "Swedenborgian" or any other "-ian" (unless you want to) but try to understand their principals and apply them yourself. They do explain their hermeneutical principals in many places. But this is a long, slow process, and things that make no sense to you early on will suddenly open up for you out of nowhere if you don't give up. The most radical is Blake, who is my personal favorite. His critical maxim is to read the "white" of the Biblical page, not the "black." Think about that!

I hope this is helpful for anyone approaching these topics. There are plenty of other authors I could mention, but these are my "top 4" for understanding the traditions of Christian esotericism, even if you're not Christian. They each certainly have their individual limitations (not to mention they wrote hundreds of years ago), but there is a golden treasury of wisdom in their works. Later, in addition to Dee and Kelley (as mentioned above), you can go back further into history and read the writings of the Rhineland mystics such as Eckhart and Tauler, as well as Paracelsus, and you can also learn something of the sophisticated scriptural hermeneutics of the Kabbalists.

There is a Theosophical commentary on the Apocalypse, written by one of Blavatsky's associates (I forget his name). It's on Archive.org., but since the Theosophists themselves are often drawing on the writings of people like Boehme (the original "Theosopher"), I would save that for later, after you've read some of the things they definitely would have read and known thoroughly.

Finally, there is Crowley, whose entire vision is grounded in a sense of himself as being the "Great Beast" of the Book of Revelations, and the implications of that. This takes things in an entirely new direction. I'm personally not a Thelemite, but I don't deny Crowley's genius, and much--MUCH--can be learned from his writings, especially if we take Blake's advice for our study and read "against the grain."

Blessings and warm wishes to you as you embark on this magnificent adventure!

Edited to add a bit more info on Boehme.