Agents in the US would just be normal citizens asking for money/crypto. You'd need to find fools to deceive, but a lot of people fall for scams to get small gains. Many hard drug users in particular are often rather self centered in my limited experience.

Or if you wanted to attack refineries, you could possibly select some climate change activists to do it for you?

Or find angry children to do it. Make things go bang for fun.

Our industrial infrastructure appears to be vulnerable to me (as a superficial opinion).

The real fix is to help poor people in other countries to like the US. And work hard at avoiding doing things that radicalise dangerous haters.