I am genuinely curious - are there any historical examples where ending diplomatic relationships and imposing sanctions on a country has improved the situation for people living there?
It's not clear how much of South Africa's Apartheid collapse was due to external pressure, and how much was from internal problems.
They had widespread and growing internal rebellion for a long time, with independent internal discussions and controversies going on about the unsustainability of Apartheid - both from a moral and economic perspective. Hell, they even tried Mandela for Treason in '56 and spent 27 years in prison after he started the revolutionary group in '61.
Apartheid didn't end until the early '90's.
Saying external sanctions caused it, is a bit like saying the USSR collapsed because of embargos.
They definitely weren't helping make it stay, but it's hard to say those where why it collapsed.
