How can I express "sacrificing ease for quality" in a common expression?
To cut corners means:
to do something in the easiest, quickest, or cheapest way, often harming the quality of your work
So not cutting corners is a suitable way to express this. You could say "I don't cut corners (when doing my job)."
Easiness is to quality what short-term interest is to long-term interest.
When we sacrifice easiness for quality, we actually sacrifice short-term interest for long-term interest.