Above all, you have to be careful not to get counterfeit money. 
Has this ever happened before? I'd assume that you'd have to accidentally come into contact with some shady mafia group over e.g. Bisq for that to even be a remote possibility.
We have a history here of money exchangers that work only with paper money, even in 2023.
I confirm this.
But then how are you going to carry all that cash around? Let's assume you withdraw even $50,000. It will have to be declared when you leave the country.