Big tech using AI applications to oversee and help coordinate the fraud across state lines, needing a bird's eye view in order to strategize and deliver orders to paid operatives in the polling places. There plans were adaptable, but it is the adaptations that people saw being put into place on election night, due to this system, that caused the public to become aware and cry foul. The machine brain being used to coordinate the planning on the fly is why things went sideways and looked so janky to the human observer, that, and the overwhelming amount of fake votes needed in multiple states to win. They never programmed the machine with a maximum threshold level failsafe that would make it virtually impossible to not be detected. Either that, they didn't care, or they were already in neck deep with their prior actions. Given their activities since then, I'd go with a combination of all three.