This is all really good stuff, and thankfully I feel like I have been practicing a fair bit of this already (so, I could be biased here!).
I like the umbrella callout especially, that one took me a few years to really internalize. "Protection" isn't as beneficial as "good stress" is. You don't just protect muscles, you use them in a responsible manner to get stronger. I've started trying to ensure my team gets a lot of "good stress" (so projects that grow careers, develop expertise, etc), while getting some concentrated down time after to rest, reflect and grow (often it manifests as time to fix bugs and just not be the star of the show).