There's a famous literary analysis essay about this, The Death of the Author, that argues for the latter. I happen to strongly believe this view.
I decide what a work of fiction means to me, and since it's a work of fiction there is no "higher" meaning than that. Other people can of course present their ideas about what it means, and if I like those ideas I'll adopt them into my own thoughts on the matter. The creator can be one of those "other people" but he gets no special role in the argument; he has to make his case just like anyone else and I feel free to say "no, that's dumb. I think it means something else."
I think we're already in it. A world war, as I understand it, is basically just a situation where a variety of alliances and tensions build up until when a war erupts in one spot it rapidly spreads around to involve a large number of countries world-wide. That seems to be the case already, you can easily build a Pepe Silvia wall-of-crazy showing all the connections between Russia and China and Iran and Syria and Israel and Hungary and Ukraine and Belarus and the United States and Taiwan and on and on. The actual shooting pew pew warfare is still relatively confined (though bear in mind that literally a million Russian casualties have happened over a thousands-of-kilometers-long front line riddled with trenches and minefields, which is pretty significant) but all these countries are throwing their weight in on those fights and it's easy to imagine them branching out quite quickly when conditions change.