Intellectual/creative Latin American writers

I've been brushing up on my Spanish through app-based learning and while it has been enjoyable and fruitful I was lamenting to a friend today that no matter how long I go down the app's lesson plan I will always be speaking and writing in "instructional Spanish." I won't enjoy the facility with the language I do with English. The way I phrased it to him is that I'll never learn what the Spanish word for "inchoate" is.

That got me thinking. Who are some Spanish-language Latin American writers who would be characterized as intellectuals or who are acclaimed for their use of the language? Who really knows how to construct a sentence and has a robust vocabulary? Fiction or non-fiction. There has to be publications equivalent to the New Yorker in Latin America. I'd appreciate any recommendations. Then I can peruse the writings and then check out some translations and such. Thanks!

Edit: I bought a copy of a book of short stories in English and Spanish that featured a few of the recommended authors. No Borges. Maybe I will build up to him. Also bought a copy of an Orsai collection. I will, charitably, be able to understand half of it, but it seemed like a cool thing to have. Thanks for the recommendations, everybody.