Different intelligent agencies have confirmed numerous deaths as well as reputable journalists from multiple witnesses. I’m sure some are exaggerated and run wild with but there is too much evidence to suggest ALL are fake
Some of the deaths have been confirmed. As far as I'm aware, though, none of the ridiculous methods of execution reported in the media (shot by anti-aircraft guns, torn apart by dogs, etc) have been confirmed. Moreover, the recurrent nature of these rumors suggests that they're long-running myths about North Korean execution methods that get attached to whichever official is rumored to have been executed recently.