I don’t see why someone couldn’t be appointed to a second (or even third) term on the Supreme court. The point is to make the court less succeptible to fluctuation by packing, not increase them.
And why wouldn’t they go back to regular attorney work? They could take a post on a Circut court or a state Supreme/Superior court. It’s not as if their entire career will be expunged after their term ends so they have to start as if they’d just graduated Law school.
Super supper!