El Salvador is indeed a haven for Bitcoin users to conduct any transactions, including withdrawing large amounts. There's no tax, even if you're a foreign investor residing in El Salvador. Nayib Bukele has truly turned El Salvador into a haven for Bitcoin users. Although I haven't personally visited there, several news reports on the legal adoption of Bitcoin in El Salvador confirm all of this.
As long as the crypto comes from money that doesn't violate the law, you are safe to withdraw. However, it can turn into a significant problem if the money you withdraw is proven to be from an illegal source.
It is not as easy as it seems, the moment you "move" to Fiat you adhere to the rules of that country and depending on your nationality, it does not matter where you make that change you pay taxes in your country of origin.
On the other hand, "landing" with money in El Salvador, if you are not going to make investments in that country, you will have to pay a fixed +% transfer rate, they have double payment of fees, then pay the intermediary bank, finally and depending on where you sent that money, the respective rates.
And it's not that you're going to get a banner saying be careful, you can't make those Swift transfers, or we don't receive deposits, first they collect their premiums and then when you're in a conventional bank, well, it's that the laws and notifications appear.