That's going to happen because Ewers is such a strange QB. He's like the QB equivalent of a super streaky 3 pt shooter. He'll be on for a while and the offense will absolutely cook teams, then he'll all of a sudden go cold and start throwing the game away. He's somehow regressed even from last season.
He's in the best position of any QB in the country. The best defense in the country backing him up, one of the best offensive lines that can maul aggy for 250 yds on the ground on the road, a RB that is rising to legend status, and very good WRs and a top end TE. There's nothing that should hold him back and he has the most slack to make mistakes in the country. Even suck ass Mac Jones was able to absolutely destroy college football with this kind of setup under Sark.
Aggy was always going to fuck this game up because they still had something to play for. That's what they do. The blowout and shutout was right there for the taking but the dude just can't get consistently good.