If your goal is to act as a deterrent then harsher sentences do not work, at least according to research.

At this point, we think it is fair to say that we know of no reputable criminologist who has looked carefully at the overall body of research literature on “deterrence through sentencing” who believes that crime rates will be reduced, through deterrence, by raising the severity of sentences handed down in criminal courts.

https://www.crimsl.utoronto.ca/research-publications/faculty-publications/issues-related-harsh-sentences-and-mandatory-minimum