In the real world, I don't see a WWIII happening this century, let alone a Eugenics war. I guess it will go the way most things sci. fi. go IE nowhere. Terminator didn't happen, Blade Runner didn't happen, ditto Soylent Green, ditto 2001, 2010, back to the future II... Nothing ever happens the way it was predicted.
And nobody expects things to happen the way they do in science fiction stories. Science fiction stories just tell stories about (often future) events that might possibly be possible depending on whether various scientific theories are correct and on the course of future technology.
The most science fiction stories do predict is possible future trends in technology and possible sociological effects of those technological changes. But predicting the course of future political and military history? Forget about it!
No science fiction story, episode, or movie predicts the course of "The Future". If the concept of alternate universes is correct, then there are countless possible futures, many of them highly different from others, branching off every second, and so there isn't anything which can be called "The Future", but many contradictory but equally real futures that really will happen in different alternate universes. You may experience only one future and thus complain it is different from various fictional futures you remember from various fictional works, but if any of those fictional futures was scientifically possible, it actually happened in various alternate universes you have not experienced.
Furthermore, in the case of
Star Trek it clearly happens in an alternate universe separate from ours. Not only in events that happened after TOS aired in 1966-1969, but also in events that happened before the era of TOS. Since the creators of various
Star Trek productions did not always describe historic events accurately their historical errors put
Star Trek in an alternate universe than ours, regardless of the intent of the creators. Any story which depicts past events differently from the historical record is automatically in an alternate universe which diverged from our sometime before the historical event, regardless of the intent of the creators, regardless of whether the creators ever even heard of the concept of alternate universes.
I may add that I comment on the various world wars in Earth history in post number 16 in the thread:
https://www.trekbbs.com/threads/your-last-so-called-world-war.300954/ and post number 219 on page 11 in the thread:
https://www.trekbbs.com/threads/the-omega-glory.296189/page-11