Austin Davis and broken down Manning had similarities
Defenses didn't have to defend lots of the passes because they both couldn't make them. But Manning still had the ability to make just enough plays in a crowded field to avoid mistakes provided the defense dominated and the team didn't need to score much.
Davis won't have that knowledge of the QB position to do that.
Davis is a good 1-2 week QB. Once a team prepares for him and the field gets crowded, it becomes so difficult for him.
And with the Rams predictable offense it got worse.