This SI article is a good read. It sheds some light onto why doctors from the different conferences disgaree about playing fall sports.
https://www.si.com/college/2020/08/14/ncaa-football-covid-medical-experts-big-ten-pac-12
https://www.si.com/college/2020/08/14/ncaa-football-covid-medical-experts-big-ten-pac-12