I think a fair and equitable way at to handle the power of SCOTUS is to have a review every 12 years of service. Only 3 would be up for review at a time. This review would happen in the 3rd year of the president’s term. If the justice is doing well, Congress, Senate, and POTUS all believe the justice should continue to serve, then they would get another 12 year term to serve out. This would allow for the justices to have a period of reflection to retire if they so choose. And every president would have an opportunity to influence the courts after they are no longer in power. Additionally, we would not have these justices who are hanging on due to ego when they would be better to step down for the new justices to make decisions. If the president feels the justice should no longer be on the bench, then there would be a list of potential candidates prepared in the first half of the POTUS term. Every president, blue or red, would have the say and potential to change the Court. Yes consistency would be nice but it has become clear that that isn’t a possibility anymore.
If there is a disagreement between Congress, Senate and POTUS, there would be an independent committee of attorneys from both sides of the political aisle, practicing attorneys and scholars, who review the materials and then make their recommendations. The president would have the final say in whether or not the justice should step down.
The second part of this topic is to institute minimum qualifications beyond a barred attorney who may have been a judge at one point. I think the justice candidate should have served on the bench for a minimum of 10 years prior to the appointment and an additional 5 years of either practice or scholarship prior to the appointment. This would mean 15 years experience would be required before sitting on the bench.