What questions do people have about the Book of Revelation?

I recently recorded a 'fireside chat' on the Book of Revelation for a conference of the Christian Residential Network. Keith Hagon asked me a number of questions, including the ones below. For fuller exploration, see my Grove booklet: https://grovebooks.co.uk/products/b-28-how-to-read-the-book-of-revelation

and my IVP commentary: https://ivpbooks.com/revelation-243

What sort of writing is it?

Based on an answer of letter, prophecy, apocalyptic, etc, with symbols, numbers, etc, how do we read it - that is, how do we know when it's to be taken literally (as in the 7 actual towns) and not (the horned beast)?

Why was it written and what are we to take from it now? (To include who to, when and by whom)

Does it speak to our environmental and ecological concerns - especially if God is making a new heaven and earth?

What are we to make of the present-day applications of it i.e. end time timelines and prophecies e.g. bar codes, the EU, etc.

Can you explain or elucidate on the following:
rapture/millennium
144,00 and their seal
the mark of the beast
the Antichrist
Babylon