In effect, the ability to sign away those rights generally, rather than in response to settling a specific incident of wrongdoing, gives employers terminating a employees an incentive to fuck them over so as to maximize leverage.

Perhaps better is something where anybody signing away the right to sue over discrimination has to do it under the supervision of the state's workplace anti-discrimination regulator? That would remove the information asymmetry that the employer has here.

Please, no. I can already predict the outcome: government bureaucracy slows down the whole process to a standstill, corruption/kickbacks become the norm. Meanwhile, employees still keep getting screwed over.

That's the point. That shouldn't be possible. I should not have to waive my rights to collect severance. That should just be given by default.