I've spoken on this excessively.
Which war do you deemed as the first real world war?
In short;
It's no "should"; what we call wars what we colloquially call them. It seems like circular reasoning but that's literally just how it is. We call things certain things because that's just what we have always called them.
Ultimately the term 'World War' brings with it a sense of worldwide scale and popular participation from all corners of the Earth that, frankly, was both not possible and did not happen until 1914. Even then WWI was not colloquially called such until its connection with the Second World War was made in 1939; it was simply the 'Great War'.
So the term itself is extremely arbitrary; honestly the only reason I've ever seen previous wars disputed as 'the first REAL great war' are by bloggers/vloggers trying to bait viewers into watching them challenge 'the man' or 'the narrative' because controversy sells.
Honestly the term is just utterly meaningless from a technical standpoint. Every attempt to justify what constitutes as a 'world war' ends up in being a game of who can be more pedantic the quickest. May as well call the Gulf War a 'world war' since it involved European, Asian, and American powers or the Korean War since it involved fighters from basically every continent. See what I mean? It's just a term we apply to two loosely interconnected wars whose scales surpassed all before and have not yet been surpassed, not some academic term that is made by a cabal of historians.
hi! There have been several questions in here asking about the Seven Years War as a 'world war'; check out these discussions