Or just disable notifications for the various apps you don't want to hear from.

That's opting out of notificationse which is subtly different. I'm advocating for something a little different. See if your mind feels less scattered if you don't have any notifications at all. Then allow back in the ones that you feel are essential. A lot of the notifications we get feel important, but aren't.

I've never considered something like this before. I like the way you've phrased this too. I'm going to give this a shot for a few weeks.