Mussolini and other Italian inventors-of-Fascism figures were closely allied with the Futurism movement and Marinetti.

https://www.booksontrial.com/mussolini-and-marinetti-a-timel...

That’s Italian futurism, which was a specific movement. I think the term was being used more broadly here.

Go find some Soviet space art, or mid century American “space age” stuff, or less dark forms of cyberpunk / cyber culture from the 80s and 90s. None of that is fascist yet all of it is popularly called “futurism.” I’ve even seen the term associated with solarpunk.

As popularly used it means more or less the idea of trying to use human intellect to build or create something fundamentally new, or roughly that. It’s not a precise term more of a vibe.