I guess I have an endgame setup, if your definition of endgame means being satisfied and not changing anything. I haven't changed a thing in 3 years? 4? I lost count.
The setup is Resolution Audio Opus 21 --> BH or SRM-717 --> SR-007 Mk1. The secret ingredient is definitely the Opus 21, adding real dynamics and punch to a setup that otherwise can sound a bit bland. It's not perfect but it's lively, which is a whole lot better than a pristine dac that sounds dead. In general, the 007/BH combo needs as good a source as you can get. It's not the difference between sounding good and sounding bad, it's the difference between being mesmerizing and between making you wonder where the money goes. The 007 is always going to sound at least decent, but it's not magical until you connect it to something magical, which is what a revealing transducer should do.
I'm somewhat tempted by the 009, but not enough to spend thousands to find out. I never cared as much for a Lambda-like sound signature and prefer a warmer sound.
But then again, by the same definition the UM3x is an endgame setup too since I haven't changed that one in years either. On the move, I just don't care enough, it's comfortable enough and sounds ok. I don't really need more than that, though I may pick up an ES5 or similar if I get around to it.
The one thing I'm missing is a beater headphone to use as an all-rounder. I'm not (too) abusive on my gear but using the 007 hours daily puts a lot of wear and tear on a headphone that's not replaceable. It's likely that a lesser stat is in the future (or maybe a second 007?).
Ditto on 'stats being good for all genres, especially faster stuff like metal. You just need a beefy amp or the frequency extremes suffer.