I states the appointment is a lifetime. Please read the constitution.
Article Three, Section 1 Justices “shall hold their offices during good behavior”, which is understood to mean that they may serve for the remainder of their lives, until death; the only way justices can be removed from office is by Congress via the impeachment process but that ha snot been tested.
Lifetime appointment is not explicitly stated and not tested. Joe has not even been abiding by their rulings. It seems the precedent now is for the democRATs to just do what they want and dare the court to do anything about it. The democRATs hate Constitutional limits on their power.