How do you handle notification fatigue?

Folders and filters. If used correctly, these 2 things will make your inbox clean

Remove them all then slowly start adding them back 1 by 1

unsubscribe or block every unwanted email as and when they come. And star the one's that are important, so you don't take time to reply those. Email is still fine, I receive about *100 promotional SMS every day* (no exaggeration) and there is no way I can stop those. Any solution for that? Im using an iOS device.

Riddle me this, Batman. What percentage of notifications fall into the "must absolutely respond now" category. I think you will find that people can wait until your "email office hours" are in session. Let them know when this response window is open and then _release your mind_.

Turn off your phone and put it in a drawer while you're in deep work time. I know it's extreme but your focused attention is one of the most important assets you have and needs to be protected.