"Unique" individuals is a nonsense number. It matters little if somebody attempted before. How many of the unapprehended are non-"unique"?
The border crisis has root causes that are already well-known. The "root cause" analysis in response to what is happening now is a ruse by incompetents.
The root cause of the surge is the advertisement by Biden during his campaign. The migrants themselves will tell you that.
(Done following you down your current rabbit hole....)