The metonym "throne" refers to kingly authority like David had. Alternate translation: "kings, ruling like David before them" (See: [[rc://en/ta/man/translate/figs-metonymy]])
This sentence lists all who will be powerful and wealthy. This can be stated clearly. Alternate translation: "he, his servants, and his people will ride into the palace on chariots and horses" (See: [[rc://en/ta/man/translate/figs-ellipsis]])