Actually you are wrong....monarchy is not the most natural form of gov't for people. Even God preferred we not use that form...it was weakness and self abortion which caused the Hebrews to ask for a king in place of their better form...a request He at first declined....knowing better what was good for us....but we insisted and he gave so we could see our mistake up close and personal...
You are to INTERNALIZE Christ as your King so that you make right choices....this will make any form of .gov work...but it will be best suited and more probable in a freer society such as our republic.
God does not want slaves he wants us to choose rightly of our own free will.
Do you believe this regarding the Papacy as well?
You say God did not prefer the Monarchist system, yet He ordained and blessed it on every occasion through the priests and prophets, and even went so far as to rule through that system by being born into it (regardless of His simplicity). Whenever there was a change in government in the OT, there was no establishment of a republic, just a change in monarch.