Good thing about GitHub is that if you have email notifs enabled, they put a fake CC in the email

    {review_requested | author | assign | mention | your_activity | subscribed} @ http://noreply.github.com

Then you can create filters in your email client and sort this stuff into different subfolders.

IMO this is still not enough granular (https://twitter.com/__jakub_g/status/1222918835172495360) but overall it's quite ok. Feel free to ping GH support if you agree with my tweets so maybe this gets prioritized.