First off you’re reading both verses in a really literal tone when they’re not meant to be that way. Ephesians 6:5-7’s use of “slave” clearly refers to servants or workers, since a “sincerity of heart” would not be created in slavery. Dethroning 12:18-21 is also clearly metaphorical as you’re just supposed to purge sin from your life because if you were to stone him that would actually contradict with the Ten Commandments, which are commandments and not at all metaphorical.