The law suite you speak of would be decided by the Supreme Court with the two most recent appointees directly and personally affected by the law and therefore by law, one of the few that applies to Supreme Court Justices, could not participate.
But to the point of constitutionality, Congress has the power to determine the size and budget of the federal courts and although it has been at least 100 years, has previously reduced judges in the federal courts.
Gorsuch and Kavanaugh would not recuse themselves, and, again, there is no guarantee that the judges reduced would be the ones you might want. And, again, shrinking the courts is the exact opposite of what the court system needs right now…there are too many cases taking too long for justice to be served. Put more judges on, and you have more slots open to fill, and circuits to switch to liberal majorities. That’s not controversial, Republicans have been saying we need it, as has Roberts, so if Biden gives them that they won’t be able to argue against it honestly. And, even some Democrats won’t be in favor of shrinking, and judges will speak out about it too because of the increased workload.
You’re view is really myopic, there are multiple ways to deal with the Trump judges, and your way is about the most awful in terms of the politics. Leave them there, then no one can complain they were removed unjustly, and add new judges (which is a standard thing), and everyone will forget about it, except that justice will run better. You have to be smart about these things, not emotional.
For one, his “peeps” are lawless psychopaths who don’t care, and don’t follow the rules or laws, they just do all they can to carry out the GOP’s fascist racist greed and hatred.
For another, you can’t leave them to operate unchallenged and unopposed in the dark, they must be opposed, forced to work harder and spend their precious resources and time if they want to achieve their viles platform.
And for another, we need these assholes exposed, we need their names and numbers, we need to know who they are, and where they are, so that we can work to be sure they never touch government again.
That’s why it’s a story.