Don’t get me wrong. I’d love to have a judiciary made up of Constitution-honoring judges, but it’s not going to happen through impeachment for anything, but criminal acts. Check out the history of judicial impeachments and you’ll see.
All I am saying is, it could be done.
A Congress and a Executive combined with a reasonable amount of public support to stiffen backbones could do it. There is nothing unconstitutional about it.