Working?

And get paid in BTC?

Are you implying that because someone lives in an oppressive country that they have no money to transact? I really dont understand your question.

Oppressive regimes tend to control money flow in/out of the country. So if you, for example, have an aunt somewhere outside that wants to send you money -> you just might not be able to receive it, or would need to give some official a slice of the pie. Bitcoin obviously can help as u can just move the money without government oversight.

Crypto is only effective in that regard if you're able to opt-in. The problem is, you eventually need to interface with the fiat currencies for your "wealth" to be useful. The first step an oppressive regime would do is to just ban exchanges.

Acquiring this "wealth" of crypto would be impossible in an oppressive regime in the first place.

you dont really need to go to an exchange to get crypto. Lots of OTC sellers, miners, etc.

There were actually a few news articles about people in 3rd world countries that survived thanks to btc, though I can't find any at the moment.

Then don't use an exchange?

Lots of people do person to person transactions.