If you are running your own node / not relying on a wallet that talks to any centralized service. And if the address was generated on an air gaped PC that was booted from CD so no trace remains. Otherwise with enough time and effort and money it can be traced. And remember, the government has all of those things.
Oh, did you run electrum on your phone while connected to the Wi-Fi that is in the building. Don't think THAT was not logged if they wanted it to be.
You're overthinking stuff.
All I need to do is install electrum on a laptop and get an address and the seed of the wallet.
Erase everything, throw away the laptop, send the address to the middleman and watch the address in mempool, when the deposit gets confirmed I hand the documents to the spy, I get my passport, I fly to Salvador, and there I restore my wallet.
You don't need to be connected to anything to receive, also I don't think somebody who has done this and got enough in payments will linger that much in the states after it.
Problem is, you can't spend a large portion of those coins legally, or it will attract attention and you will get busted. So actually the best bribe is the one that can be reliably laundered, because then you can spend it on a new car or a house or a yacht.
Coming from a country that after the fall of communism was corrupted as hell, I wouldn't really care about things 10 years after the event.
The first thing that can send you to prison is to actually receive the bribe and if you don't spend it because of a guilty conscience with
BTC at least you can be safe, with any other method you're in danger, bank accounts, gold, a suitcase of money, with everyone is the danger of either being traced or having been filmed when you pick it up.
With the coins in your wallet, you can wait 10 years, become a grandpa trader, buy a 5
BTC sell 7
BTC, declare all profits, and be totally legit.
Oh, and since you're mentioning yachts, there is no way in hell and no bribery method that would cover something of that size, at that point you have to be the law, much like in Russia for example.