It doesn't make any sense for Allah to impose capital punishment for crimes like adultery and apostasy when Allah says that he forgives all sins except dying upon shirk (associating partners with God)

Did God advocate death penalty just for leaving the religion? It’s not in the Quran if it is can you provide verses.

As for apostasy it’s not simply as leaving the religion as your advocating rather if the individual left islam and Pro actively hostile toward the believers of Islam or causing issues in Public regarding religion.

Even the Prophet never put anyone to death for apostasy alone rather he let such a person go unharmed. No one was sentenced to death solely for renunciation of the faith, unless [it was] accompanied by hostility and treason or was linked to an act of political betrayal of the community.

There are ruling when individual is considered an apostate.