Code review is the problem I'm currently trying to figure out for myself. I've never liked GitHub PRs but I'm not 100% sure what I want instead (which is possibly just: it feels like it should be a VS Code plugin... But maybe I don't like VS Codes interface that much either?)

IntelliJ supports pretty decent GitHub code review in the editor. It shows the modified code in the gutter and review comments.

I use it when I need to deeply understand a PR.