Always wondered why people don't try something like physical onion routing. If there's collateral for each leg it seems like it could work.

OriginalSize

It could be something like a PO box or a package receiving company. 

By the way, using a bank account doxxes the seller too 

2bithits

Cash by mail, but that doxxes the seller which could cause them trouble in a country with a hostile government

nerd2ninja

bitcoin

Robosats and Bisq Fiat Problem (at least in Brazil)

falcoonbr

I guess you would need to use an irreversible fiat method like cash in hand or gift card. Or let them know that you will wait 2 weeks to verify received fiat so they cannot reverse the payment