Acen - Trip II the Moon (1992)
if someone else can find an earliest example (maybe in hip-hop) of pitched-up vocals over breakbeats please share, the next time in musical history I can think of this becoming used again is the Kanye West style https://www.youtube.com/watch?v=QUeYetMJfvc
Numbers and Home Computer/Computer World are highlights.
Although I really like that album, its just a logical progression of what they were already doing. I'd say they really broke new ground when they released Autobahn. By the time they did Computer World, mainstream synth pop was already a thing and it was just their take on it. Computer World was released in the same year that Depeche Mode's first album, Speak & Spell, was released (still my favourite DM work).
So by the time that Kraftwerk released Computer World, they weren't really breaking any new ground at all, just refining what they were already doing, and had been for many years. Doing it really well of course.
Around that time, Caberet Voltaire, Joy Division and Japan were doing more experimental stuff. Japan's "Tin Drum" album, also released in 1981, has way more sound experimentation on it than Kraftwerk had been doing for a few years. I boggle that Ghosts made it to Number One in the UK singles chart.
Hec, look at the first 2 Human League albums (before they kicked Ware out and got the girls in), proto synthpop back there from 1979 (have a nosey at the evergreen, still awesome Empire State Human).