Some great thoughts here Jason.
The only thing I would add is scheduled Do Not Disturb. Be sure to add most important contacts to favourites (to ensure their messages/calls come through) and set a time schedule to remove all pings.
Mine is from 8pm-12pm to minimise distraction time closer to bed and a quiet thought-provoking morning.
Thank you for the tip on Superhuman as well – I just signed up!