Yeah, that sounds absolutely awful compared to what it's like to live in Iran now

False choice. Both are bad.

Nope. Your "horror scenario" would be a definite improvement. Both are bad, perhaps, but not equally bad.

The IMF is essentially a credit union with 191 member countries, so they'd become a vassal to most of the world - if by vassal, one means to agree to terms that might make it possible to repay loans.

Some (including quite a few neoliberals) want to abolish the IMF altogether, though I'm unsure if letting countries collapse completely is really a better option.

Lies. IMF isn't a charity. They come in and dictate policy and make money off misfortune. It's disaster capitalism.

Edit: See also. https://en.wikipedia.org/wiki/The_Shock_Doctrine

I did not say it was a charity.