I went down a similar rabbit hole at the start of my PhD and I wish I’d written more of it up. One of my theories is that they combined effects quite often. For example, “harder better faster stronger” seems more likely to be a talk box recorded for a single note, then looped, then run through an AutoTune rack unit with MIDI inputs to repitch it. I mention this a little bit in a talk I have at ADC 2022 https://youtu.be/uX-FVtQT0PQ?feature=shared