It’s not a conspiracy, at least not an inside job; Trump would never agree to this. It was less than a centimeter from killing him or giving him permanent brain damage. And people died. That’s not how inside jobs go.
As I understand intelligence, Secret Service, and VIPs, the only way they get assassinated is when their inner circle lets it happen. There is no way they left that building unpatroled. I heard early reports that the Secret Service had eyes on the shooter but didn’t neutralize with prejudice. We have a dozen stories, many confirmed, of federal LEOs radicalizing individuals, getting them arms, and convincing them to commit violent crimes.
AFAICT, the debate over the little details is the distraction from how the security system functions. There’s no question that there was deliberate knowing involvement by some level of federal law enforcement with the shooter.
There were cops on scene who had eyes on the shooter for minutes but didn’t do anything, so they did have a patrol on the building; my personal belief is that if there was any conspiracy it stopped at those cops and didn’t extend to the inner circle, but there probably was no conspiracy.