"Why don't you just do US elections the simpler/better/different way we do them in my country?"
The varied structures of the federal, state, and local governments means that
US ballots are the most complex in the world. We vote on LOTS of things. Here's a 2016 ballot from San Francisco: https://webbie1.sfpl.org/multimedia/pdf/elections/November8_2016.pdf
Maybe this isn't ideal, but "simplifying" US elections isn't simple. It would involve deep (constitutional) changes in the way the federal, state, and local governments are organized.