Our Founders chose a Republic form of government because it was based on the Rule of Law which gave the people power and freedom and restricted the control of government. They knew that on the left (Monarchy, Dictatorship, Socialism, Communism,) there would be a majority of government control and on the right (Anarchy) there would be no government (with riots, looting, no personal safety). They also knew that Democracy was mob rule (with few laws). They knew all this because of actual results in history (Kings, Popes, Conquerors, Roman Empire, early stage French Revolution).
Our Founders understood there are actually only 2 forms of sustainable government: Oligarchy (visible leader with supporters/elitists) or Republic (Rule of Law). Eventually all non-Republic forms of government become an Oligarchy (e.g. Hitler or Lenin lead a revolution under anarchy and then take control of the government; democracy “mobs” cause havoc and erode quality of life and some element takes control… usually by force).