It's A possible narrative. One amongst many. Discernment is necessary to ferret out the right one (best fit to reality), which requires being able to dispationately simultaneously consider many possible scenarios, or narratives (models) as you say.

But is it wrong? And is it really?

From what I can observe it's falling into the same zone as Biden's cognitive health; the liberal establishment is not promoting a "staged" narrative, but the liberal base fervently believes it.

Rather hilariously, the liberal establishment narrative seems to encompass the least probable interpretation of the facts imaginable: that a far-right Trump supporter shot Trump due to his violent rhetoric, and that the Secret Service did their job effectively.