Boil the ocean: Do the impossible. “Let’s not try to boil the ocean here, maybe just harvest the low-hanging fruit.”
Amazingly, there are many more terms available. Please do remember all this in your new role. And here’s one more definition for good measure:
The consultant: Someone who takes a subject you understand and makes it sound confusing, and for these efforts is paid fantastically well.
Best of luck out there!