What are the mechanics of changing the a US Supreme Court Justice's term

I was going to say that other judges could do it, but it’s kinda in their vested interest to support is so that more judges become Supreme Court justices.

Still, there’s one other option: what about Congress’s power to state that a law is above judicial review altogether?

If there’s any type of law where adding that clause wouldn’t be a slippery slope (which is the main reason I understand that Congress tends to not use this power), it would be one that’s actually about the judges.

See this thread for a discussion:

We wouldn’t be able to promote any existing judges for the next couple of decades because every one of them sitting at the bench now is a political hack. And all of them will be for quite some time if the amendment doesn’t apply to all judges.

Not that prior experience on the bench is all that necessary or even desired. I do heartily agree with your idea, but there’s zero chance of it being implemented.