There are different studies which show a shockingly high percent of the population are fools but the most compelling is the one by Cambridge Analytica which found a population cluster in Facebook's massive amount of user data. They called this the average cluster.

The Republicans targeted this group in the 2016 election. Around 30 percent of the b population fall into this group.

I don't recall if this is where I originally heard it but it gives you a place to start: https://www.pewresearch.org/short-reads/2024/02/28/who-likes-authoritarianism-and-how-do-they-want-to-change-their-government/