It’s hard to win as a NK to begin with. It’s also very hard for a NK to become the king. And it’s especially hard to win as a Psycho King.
Therefore, I suggest replacing the Psycho King’s tenacity with Psychotic Tenacity, which grants all the usual benefits and also makes them immune to being killed at night (but not to poison or bleeding, so a butler can still get them.) This wouldn’t carry any real risk of outing the king, since they can simply claim to have guarded.
It’d also prevent election as the Psycho King from being a downgrade, since currently the NKs that become the Psycho King are mostly night immune anyway.
Possibly, Psycho Kings should also have unlimited uses of guards, for the same reason. It’s already difficult to become the king as an NK, and any town foolish enough to make that mistake deserves to suffer a bit.