Enlightenment cannot be defined by the strengths of monarchies, especially in the time of glorious revolutions. Enlightenment aims to advocate the state government to promote the system that will allow people to hold power in their respective society.
However, in monarchies, the kings and influential people were the only people who were close to the state government and were the ones to make the right decision. This is the primary reason why the enlightenment does not fit in the monarchy government.