They played no one for about 3 months except Clemson who beat them. UL had them on the ropes in the ACC championship. I think it’s fair to have some questions about how good they really were.
But they can't help that. They can only play who is on the schedule. And in those games they didn't just go 19-1 in the ACC, they outscored their opponents by 0.33 points per possession.
You don't see numbers like that in power conferences. Even weak ones.