and couple it with adding States like Washington D.C. to protect the Supreme Court majority from future republican controlled Governments.

I'm checked out on anyone suggesting term limits as a solution. That's never going to happen, because it requires a constitutional amendment with 2/3rds of the Congress and 3/4ths of States to ratify it. There will never be the political will for that. Politicians benefitting from the Supreme Court aren't going to vote to give that up and neither will the voters that support them, because it's transactional.

If we ever had the political will to add term limits to Supreme Court Justices we wouldn't even be having this conversation, because if we did we could pretty much pass any law we wanted without much opposition.