This problem is fundamentally impossible to solve. Once data has been created, it's trivial to make and transmit copies. Complete tyranny would be necessary to erase all illegal data from all computers in the world. The best people can hope for is removal of data from popular centralized services.
The 'good' news is that with deepfakes everyone will (soon) at least have the veneer of plausible deniability. I know there will always be ways to determine whether something is a deepfake via adversarial detection but perhaps in the future so much content will be faked that unless it is a head of state or other renowned person, only then would it then be worth checking.
