It's the recruiting. The 2020 class was ranked 71st in the nation. That is a huge drop off what it was with Herman.
In regards to who the back up quarterback is, there appears to be no clear cut consensus on who it is. When I googled it I found more mentions of Massoud as back up on the depth chart. If we lose next week against Rice I think we will know for sure who is next in line at QB. And maybe they will also put a fork in Holgerson.
Case Keenum and Geno Smith are why he looked so good. He lucked into both of them. At any rate, he flat out sucks now.