It’s not immediately obvious, but you pass the display input to the Pi, have it return the auto-aim coordinates or draw some boxes for wall hack and send it back to the main computer.
This isn’t the only method either. People replace their ram with a physical device that allows it to be read two times, once by the cpu and once by your hack device. There are like 5 different ways to avoid kernel level anti cheat.
I know little about Ultimate meta. But this seems like cherry picking stats. Imagine playing the 45%win rate guy against the 55%. Just because the average is 45% for the one fellow doesnt mean that his chance in certain matchups is always 45%, it could easily be 0 in some cases. Conveniently Sakurai doesn’t mention the matchup win rates.