My jaded, knee jerk response was going to be "build a dictator proof system and the world will build a better dictator". I don't want to be hopeless on this so I'm honestly asking about your ideas about it.
We need to invest effort into researching how to make quick, high-quality decisions as a collective. Large concentrations of power emerge because we haven't yet discovered how to make effective decisions democratically. Representative democracy is not good enough. We need a robust system of direct democracy capable of producing decisions that are at least as good as those made by a skilled small group.
Innovations like blockchains and LLMs might finally enable us to develop such a system.
> We need to invest effort into researching how to make quick, high-quality decisions as a collective
Getting rid of First past the post voting systems will reduce incidents of extremism. Ranked choice voting, multiparty systems amd coalition governments would be an improvement on the current American status quo.
None of that prevents extremely wealthy people and organizations from buying enough politicians and media to corrupt the system. Europe has a lot of those things and is struggling with the same issues as the US. We need to either prevent such concentrations of wealth or create a democratic system that money can't corrupt.