My solution is to organize my PRs as a sequence of commits that explain what they do, and then a PR description that gives an overview and motivates the changes. I've gotten really positive feedback on this, and it dramatically speeds up reviews of my code. Overall less work for the team. (And it often helps me find problems before I even submit the PR.)

As for other people's PRs? If they don't give a good summary, I ask them to write one.