Is it permissible to shave pubic hair and armpit hair with a shaver that does not remove it completely, but rather greatly thins it? And could you provide us with the story of the Companion who thought the villagers wanted to fight, so he killed them all, and then the Messenger of Allah, peace and blessings be upon him, became angry about that?

There is no harm in removing pubic hair by any means, such as a "machine," for the intended purpose is the removal of hair, and the retention of a small amount does not preclude permissibility.

As for the story of Khalid ibn al-Walid and Banu Jadhimah, it was narrated by Al-Bukhari from Ibn Umar, and in it, the Prophet, peace and blessings be upon him, disavowed what Khalid had done.