For all the people talking about 5 hour PR review delays... This reminds me of some teams that rotate the "fire extinguisher/emergency bug fixer" duty every day/week/sprint to a different developer. One could rotate a dedicated "first review duty" person. That developer would be in charge of focusing on rapidly starting PR reviews as their priority, with option to request other reviewers if necessary. Spreading the duty around would make people be respectful of the reviewer because if they send unreviewed slop to the reviewers, it's likely that people will send them slop too.