The bigger omission is Byatt's Possession, predating The Secret History by a couple years and I think possibly being the type specimen of what is now called dark academia.
Not a clean fit to Dark Academia, but a lesser known and worthy forerunner.
Also, Jonathan Rhys Meyers, Stephen Fry, and many others in the 2000 TV adaption is good entertainment for anyone with a DA bent. - https://www.youtube.com/watch?v=wsPC8m4zo9g
The Secret History is generally regarded as the prototype for the modern subgenre though.
> The Secret History is generally regarded as the prototype for the modern subgenre though.
Well, but that's why I mentioned possession. I know the secret history is considered the original dark academia, but possession predates it, is retrospectively just as firmly within this genre as it is understood now, and while not as famous is probably as influential on authors within it. It's a striking omission in an overview of the history of the genre.
Vita Nostra definitely fits the genre descriptively but I think it's more connected to a russian fantasy/slavic magical realism tradition that there isn't really a name for and that we only get a little bit of translated decades later. To me it shares a lot more with like mariam petrosyan and sergei lukyanenko than it does donna tartt.