What do you think can be done to mitigate the risk of cryptocurrencies being used for criminal purposes? What measures should be taken?

what is important to increase is the moral awareness of everyone who uses Bitcoin and Crypto. although there will still be clashes between those with good morals and those with bad morals. because after all we can't force those who have bad intentions with the use of Crypto. control will not be possible. those who do bad things like scammers will continue to do it until they realize their own mistakes.
actually Bitcoin and Crypto is a good update. it's just that those who are irresponsible use Bitcoin and crypto as a tool to commit crimes. the fault is not Bitcoin or Crypto. but they are wrong in using it.