Iran, Iran, Iran, 
There's a theory that Iran was somehow behind the assassination attempt. I'd think if that were true, the 20 year old would not have had to ask his dad to borrow the rifle. He would have been given one or paid enough to buy one himself. Seems like the circumstances speak more to an inexperienced kid trying to make the history books and less like a foreign power with massive resources backing the shooter.
Anyway, the theory goes something like:
Iran was terrified of Trump being President again, especially considering their conflict with Israel. If Harris were in office, tey could do whatever they want, and the US would continue to blame Israel when they defend themselves by taking out military leaders and targets.
Once they succeeded, they'd tell the Harris administration how to play ball with them. If they don't, Iran would tell the world she and her people conspired with them against Trump. I'd bet they's have emails and messages that show a pattern of communication with the foreign government leading up to the rally.
I don't think the results were as expected. To take credit for a botched attempt now would be stupid.