plenty of words and phrases originate from fiction
quixotic, scrooge, shangri-la, Uncle Tom, gargantuan, kafkaesque, blurb, milquetoast
and words like cyberspace were first used in fiction
once real people use them, they stop being fictional words
Kafkaesque doesn’t originate directly from fiction like your other examples any more than a word like Dickensian does.
The word was "Brobdingnagian", which apparently means "giant", from the book, Brobdingnag, published in the 1700s. I know all of the words you listed, even if I don't know t he books they came from, on the other hand, I've never heard anyone use "Brobdingnagian" and I've never heard of the book it came from either.