I want to ask for solutions how it can be solved to catch more Blockchain fraudsters and prevent fraud.
It shouldn't really concern you unless you are the police or you run an important crypto service (maybe an exchange, casino, or mining pool).
You have to think at the level where it's most likely going to hit you - that is, scammers. How to avoid getting scammed by them, recognizing their dirty tricks and other signs that they are pulling off a heist.