Low turnout for primaries produces non majoritarian choices, while I'm interested in proportional representation systems but who picks the candidates? Also, re

Low turnout for primaries produces non majoritarian choices, while I'm interested in proportional representation systems but who picks the candidates? Also, realistically we vote too often, and on too many things - the last time I voted, I had no less than 26 offices to vote for, I'm a reasonably well informed voter, and I had no idea who 3/4's of those people are and in some cases, what their office did. I'm if the opinion we don't need more choice, when so few people show up to do the choosing. Im interested on your ideas to solve it.