Thanks for your thoughtful questions. Really good point you got there.
I would say creating a life of greatness and excellence is, and should always be, the end goal. However, on your way there, you’ll undoubtedly have to spend some of your time on some tasks that may be “mediocre.”
The important part is the overarching goal; you can work somewhere or on something and tell yourself, “This is not what I want to be doing long-term. Still, I’m willing to do whatever it takes to reach my goal.” That way, you can turn those mediocre-type tasks into learning opportunities, strengthening your resolve while developing your humility.
I believe starting out on less-than-ideal projects on your way to greatness is acceptable and sometimes even necessary — as long as your keep your big goals in mind!
Hope that helps.