Sorry, but your cute idea that Austrians only wanted an apology and for lack of it WWI started is truly just fantasy, but whose exactly?
The real truth is that with prodding from the Kaiser’s High Command Austria issued a (iirc) 10 point ultimatum, which the Serbs accepted in whole except for minor modifications to one point.
That was the start of WWI, FRiend.
It’s all in the book.
Read "THUNDER AT TWILIGHT" for starters.
You apparently are stuck with your opinion, that you read in one book, without understanding the entire picture; nor what preceded it all, diplomacy of that time, the complete player list, nor why that war could have been at the least, somewhat forestalled.