Look, you really need to educate yourself from something other than comic books. Study the subject a bit. There was no such thing.
Everybody had rights, privileges and duties in the feudal system. That included the king. Those kings who abused their throne were quickly removed because their power was checked by the rest of the nobility. That -- not the consitutional artifacts we have today -- was true separation of power.
The "people", too, had rights and obligations. They were not a homogenous class: some were freemen, or merchants, or clergy, others were serfs. Serfs had the least rights.
The future feodalism will not be like the old. For one thing, earned nobility will probably predominate over the hereditary one; we are not going to have serfdom. Absolute monarchy is indeed contrary to the American character and is not likely to ever be formed here. Much will be decided by a vote, but that is not a foreign idea to the original feudalism. The great difference will be techological: we can form separate social units in the same geography, and we can easily relocate. The patchwork of confessions, occupations, social arrangements, levers of power can be much richer today.
The right to petition the Government for redress of grievances is included by our founders for a reason - because it was NOT a recognized right under feudalism.
Your idea that “true” separation of powers is a Baron saying “King - your son is out raping peasant women - please put a stop to it.” is truly delusional bootlicker.