en_tn/2ki/23/20.md

He slaughtered ... he burned

It might be best to translate so that the reader understands that other people, perhaps Hilkiah and "the priests under him" (2 Kings 23:4), might have helped Josiah do these things. (See: rc://en/ta/man/translate/figs-explicit)

he burned human bones on them

You may need to make explicit why he burned the bones. "he burned human bones on them so no one would use them again" (See: rc://en/ta/man/translate/figs-explicit)