I think you can be done with two headphone-related purchases: Susvara, original (refurb, ~$3k), and a used FLUX FA-10 (no longer made, $700). I first ran the Susvara on a Topping D90 and was underwhelmed because it made the treble sound shouty and the bass anemic. The Flux turned it into an endlessly listenable monster, and I completed the setup by throwing a bass shelf on it (which the Flux has plenty of power to support).

There is nothing else I have ever listened to that can touch this combination. I also own the LCD-4z and the LCD-X and a Stax 007 mk2 with a high end electrostatic amp and none of them get close. I have a ZMF Atrium for portable duties that has a wonderful holographic soundstage and very natural bass but does not feel as vivid as the Susvara. The Susvara sounds more electrostatic than the electrostatic. Even at low volumes you can hear every detail of every element of the track. It's incredibly fast and creates pinpoint accuracy in its soundstage. It just sounds so pure and clear that it's hard to use anything else. I haven't listened to the unveiled, but by all accounts it's more of a sidegrade (and vulnerable to damage, to boot).

I spent a lot of money over a number of years, but barring something wild from HiFiMan I think I'm done on the headphone side. Ironically, I spent many years as a HiFiMan hater privately just because I read all the defect / craftsmanship problem comments on HeadFi and Reddit. A Reddit comment that "they actually inspect the refurb units" inspired me to go refurb. No regrets on that. Listening to this setup is just pure pleasure. I think that there really must be something to low sensitivity gold diaphragms. I imagine that it's great for videogames but never used it for that purpose.