First of all, he has a 5th year qb who, while unable to carry the offense against top 10 teams, has proven effective at beating the rest of the mediocre teams on the schedule. Like in 2019 given the schedule, 10-2 at a ought to be a minimum expectation without batting an eyelid. On top of that, Rees won't have any play calling on tape giving opposing DCs little to work with in terms of tendencies.
But the tale of the tape will be 2021 when Rees will have a year of tape and will be breaking in an inexperienced qb.