From that location you did not have a clear shot of the Rose Garden. It is occluded by a tree & Building. I accept that you didn't see any activity that would point to an event, at the time you were on location. There also seems to be continuity differences on the weather between when you were on the ledge, and that of the skies in the "Biden Rose Garden" footage.

The problem is that we have no idea when or where the "Biden Rose Garden" event was filmed. For all we know it could be a mix of past 2020 Trump Rose Garden footage blended with CGI, green-screen, or other. Biden has most of the Hollywood Movie Industry supporting him.