Las, I agree there is a Mitzvah to est a court and enforce, I am only pointing out regarding Death Penalty on all these…Despite saying ‘Chiyuv Misah’, it can be Beyudie Shomayim or that B”D has a “right” to punish by death.
I think there is a Meiri in Sanhadrin who explains, that was the Taynos Yaakov had to Shimon and Levi, that although Shechem had a Chiyuv Misah, they did NOT have to do it. They could have been lenient and punished them diff ways. (Otherwise, why was Yaakov upset as per Rambam, that it was a definite Chiyuv to enforce it by death…)