The Whore of Babylon is Jerusalem/Judea as a whole. MB is referred to as a city, and as a place where saints are massacred by the Beast. Jerusalem is named several times in the Bible as the only place where saints can be killed.
The Beast is the empire of nations servile to the Jews, a well-known idea on these forums. The Beast turns against the Whore, meaning that America, the EU, Russia et al will converge on Israel and maybe the Jewish diaspora and destroy it.
The 7th head of the Beast is the king who rules them all. 45 is the number of Saturn, and it is also the number of our president. DJT is the 7th head of the beast and the one who will lead the Beast's armies into Israel.
Up to this point the prophecy in the BOR is basically identical to prophecies of the destruction of Judea all throughout the Old Testament, but unlike in the Old Testament, this is viewed as something somewhat tragic, whereas in the Old Testament it is viewed as divine retribution for Judea's misdeeds and disobedience. This is only my interpretation, but I think that the "apocalypse" named in the BOR isn't some extinction event for humanity, but a re-interpretation of Judea's destruction. It is not something that really needs to concern anyone who isn't a Jew or a member of the Beast's army, and in the latter case, you'll have God, force of numbers, and force of arms on your side, you don't really have that much to worry about in all probability.
If you think about it this all makes sense given the way all political movements seem to turn recently. Bolshevism was started as a Jewish golem but ended with Stalinist purges of Jews. If you go to Berkeley now there's a 75% chance that the only protest signs are ones that concern Trump or Israel. Libertarianism back in 2009-2016 hated Ben Bernanke, a Jewish central banker. And anti-capitalist press seemed to home in on Goldman Sachs, the most Jewish financial institution that isn't openly owned by the Rothschilds. Point is that everything at this point eventually reduces to hatred of the Jews no matter what their race or creed. This points either to a vast conspiracy or a divine force moving the empire of the Beast against Judea.