I've noticed that judging by their inputs some people must be using a game controller instead of wheel. Problem with the controller is that doing small and smooth inputs is much more difficult than with wheel and pedals. ACC is perfectly playable with a game controller - or even mouse and keyboard, check out this guy https://www.twitch.tv/icey0082 - with the right settings.   I found some kind of settings guide here https://coachdaveacademy.com/tutorials/ultimate-assetto-corsa-competiz