I've long advocated for a few variations of this:
1. fines must conform to a percentage of the targets earning wealth (e.g. someone who makes 30K a year gets fined $3000, someone who makes 300K gets a 30K fine etc)
2. flat out just as you said, fine must EXCEED by a multiple, the amount they gained (however, determining the gain is in many situations, requiring a lot of forensic accounting to sort out).
...now I'm amused by which Ayn Rand sycophant is downvoting me because I propose proportionality so the efficacy of punishment affects evenly across the board. Y'all are the Scientology of pop-econ.