The Petro Dollar and the US Currency Predicament Explained

This is why I'm on social media: to come across credible, knowledgable people who explain things we all need to know in a way we can all understand.
And we all desperately need to know and understand this immediately!
(I'll tell you this oddity that I've puzzled over: At Bank of America, if I want a thousand dollars in cash from my account all in 20's (we used to do a cash budget monthly, so I'd ask for that), the bank scrambles for it, explaining that they don't actually keep much cash on hand, that they have to order it. Whereas in Mexico, a person I know well has businesses there and easily goes to the bank there and gets stacks of US cash when they need to. WHY do Mexican banks keep more USDollars on hand than American banks? I just figured they're madly trying to push us toward digital currency, and it's their way of discouraging the use of cash. But this explains angles I didn't know about regarding cash being printed and shipped overseas.
Just imagine if it's in the plan to bring the US down, to have a planned time to bring tons of it back in at one time to create hyperinflation. The wars they are hyping create a legit-looking need to set this up. Just wow.