Being an Anonymous user in crypto transactions is someone's choice, therefore if I want to invest and trade crypto, I would choose a centralized exchange like binance, although binance exchanges have DEX, sometimes we will see centralized exchanges have a bigger volume, this is an option .
Nothing can stop fraud in crypto, I think we just need to be careful, because no crypto police or legal entity can handle this case of fraud if the user is Anonymous.
it's better to make transactions on a trusted exchange or choose a trusted online shop that accepts payments using crypto, to avoid fraud