jeanette Isabel wrote:

'The U.S. dollar is the current reserve currency of the world. The reason for this is, nations buy and sell oil using U.S. dollars. Some people don't like this. Therefore, they've talked about buying and selling oil with gold instead of U.S. dollars. This action will flood the market with U.S. dollars.'

How would people stop using dollars make the dollar worthless?
A switch to gold would probably make the US richer not poorer. You have more gold reserves than the next three countries combined. And lots still in the ground.
The countries deciding to wreck the dollar (and I can't see what combination could) would be doing themselves immense harm. The worlds biggest customer suddenly has no money? Who is going to want that?
I think this is stepping into the preppers fantasy territory. A nuclear war, yellowstone erupting, possibly a solar flare of carrington event size would be catastrophic. A weaker dollar not.

qjs