Everything is legal, until the government officially imposes a ban, it is not legal, at the moment bitcoin has no ban, but it is still not in the national government. It is recognized that it is money.
In my opinion, if a transaction is carried out in a country that prohibits bitcoin, it is illegal. But penalties for violations can be debated, because there must be clear rules from the country's government.
In contrast to transactions carried out in countries that legalize bitcoin, all have rules so that crypto exchange cannot be done arbitrarily without regard to the traders.