Regarding Harry’s action, they were shitty but still the best he could do and somewhat intelligent. He initially tried to restrain Dexter’s urge and direct it only at animals and the like (IIRC) but when that failed he evolved the Code. The Code worked on the basic principles of only killing killers and never being caught but was ingenious about it was how it was ingrained in Dexter through Dexter’s basic need for Harry’s recognition and thus inculcated sense of justice to allow Dexter to engage with his desires such that they aren’t ruinous by not being totally abandoned leading to building up more than what can be restrained and also don’t run wild. This also achieved the goal of ridding the world of evil.
Anyways,Baku obviously does it. He accomplished a similar moral development on Marco who had MPD born of transference of negative emotions and guilt to the identity of Rodem and a need to appease Qtarou which naturally manifested in Rodem by killing alongside a feeling of hopelessness and self haltered in his original Marco identity.