The Supreme Court should probably be reconstituted as a subset of all current circuit court judges, 11 of whom are selected at random to sit for a given session.
The Constitution says almost nothing about the how the Supreme Court should be constituted or even how its members be selected, only that we should have one. I don't see how any of its language precludes it sitting with existing higher court judges on the bench on a per-session basis.
Hell, at least that'd guarantee they'd be real judges, unlike the attempted Bork or for that matter Amy Barrett.