Mostly a good synopsis there, but I'd take issue with one or two points (or rather, just want to refocus on them - not really intending to argue).
Firstly, there is the often repeated myth that the JWs have flip-flopped around about who the King of the North is. That's not true. For the last 70 or so years at least, they were very clear that it was identified from the 20thC onwards with the German Empire (Kaiser, followed by Hitler), and then the Soviet Union after WWII.
At the fall of the Soviet Union in the early 1990s, they simply said in the Daniel's Prophecy book "we're no longer sure who it is", as it seemed unclear how things were going to work out with the former Soviet republics, but they still tended to lean towards identifying it with Russia, or possibly other similar communist/totalitarian elements like China or North Korea.
With the rise of Putin and the return of Russia as a polar opposite to "the West" (UK/USA/Europe), they simply went back to and firmed up their view that the King of the North was indeed still Russia. The fact that Putin's regime turned their judicial anger on the JWs helped to persuade them of that.
The other aspect is regarding the King of the North (and his enemy the King of the South) as portrayed in Daniel. You're right that the mistake the JW org makes is constantly seeing Bible verses as exclusive to them only, or only relevant through their own history. That's the major reason for all their self-imposed confusion around the book of Revelation, and likely why they've not revisited it for interpretation for a long time!
But that's not the emphasis of Daniel 11. The whole point is about the ongoing struggle between these two Kings through the ages - which in turn pulls in all of mankind in some way. It's not just one king picking on a tiny group of religious people, yet that's how the JWs exclusively frame the whole KotN discussion these days. Of more Biblical significance if you're going to analyse the actions of the KotN is how he interacts in his "struggle" with the KotS, as brought out in Daniel 11:40-45, and how he eventually "goes off into destruction" towards the end. Will that be at the hands of the KotS? Or by God before Armageddon (by dissolving the nation(s) involved, perhaps)? Or at the hand of Christ and his armies at the end, as seems indicated/paralleled by Revelation 17:12-14? That's what the GB should be watching.
Your point about the KotS also acting against Christianity is certainly true. The whole point is that BOTH Kings are opposed to God and Christ. Both labels originally represented opposing nations either side of God's people Israel. Both kings want to rule for themselves and are guilty of blasphemy, wickedness and the slaughter of godly people throughout their history.
One thing you have to say is that, as it stands today, the interpretation of the KotN as the UK/USA and the KotS as Russia still seems spot on, as those two powers are once again locked in political combat (and occasionally military confrontation by proxy too). From the point of view of someone who is interested in following religion and politics in the world, it's also been fascinating to see how the Russian Orthodox Church has now turned itself into a mouthpiece for Putin, clearly blaspheming against God - blessing the war and telling the Russian people it is their "Christian duty" to kill Ukrainians and die for the cause, for example.
https://www.osw.waw.pl/en/publikacje/osw-commentary/2024-04-12/a-holy-war-russian-orthodox-church-blesses-war-against-west
The only weak point is that one might make a case for the KotS being just the USA or perhaps the EU and USA, not the UK and USA, as the UK itself is a much reduced player since the days of the British Empire. However, in terms of "inheritance" and the passage of history, the USA is the "offspring" of the British Empire (which in turn was the major offspring of the Roman Empire), and the UK, while much weaker militarily than at its peak, still carries much power diplomatically and culturally through its historic impact on other nations, the global use of the English language, etc. Additionally, the EU, although united in name, has never truly been unified in purpose especially when put under pressure (as can be see by the splits over how to deal with Putin), and despite the Eurozone being a large economic market, the EU itself is unlikely to ultimately ever be a significant single world power bloc politically and militarily.
The other possibility of change to what the JWs state is that it is possible the KotN proves to be not only Russia but others who may take its side before the end. But again, the JW org did anticipate that by using statements like "Note why we can say that today the king of the north is Russia and its allies." (from a May 2020 study WT on the KotN). At present, only North Korea looks like doing that though, as even China is uneasy with Putin and the way he is acting in the region, but there are some other countries who have at least tacitly indicated sympathy to Russia, if only as a resistance to what they see as Western hegemony.
The full development of this end struggle between the two Kings has yet to play out, but I can see nothing majorly wrong with the JW interpretation except that they - as they often do - overestimate their own importance and relevance in the big picture. There was a point at the fall of the Soviet Union where it looked like that was over - the reason why the GB of the time wavered about who the KotN was, presumably - but from the occupation of Crimea in 2014, and certainly since the direct attack on the whole of Ukraine since 2022, it seems the Cold War is blowing hot once again!
TLDR: 1) the JWs have not flip-flopped or shown confusion about who they believe the KotN to be in recent years, and 2) the account in Daniel between the two Kings is of significance because it is an ongoing struggle between two major powers (or power blocs) which has hugely influenced the direction of nations through history and is still doing so.
