I have tried several headphones in that range (HD599, HD58x, HD6xx, HD560s, SHP9500/9600, Fidelio X2HR, PC38x, G4ME ONE, AKG K712 Pro) some of them I used exclusively for months like the SHP9600, HD6xx and HD58x.
Somehow I still find the HD599 SE to be the most enjoyable headphones in this category. They’re like the perfect balance of fun, detail, soundstage and clarity. They’re not too fun like the X2HR, not too detailed, but just perfect for me. I compared them against the HD560s and honestly the 560s were almost my least favorite headphones but I’d choose them over SHP9500 and the gaming headsets (PC38x and G4ME ONE). The HD560s had more clarity but the soundstage was noticeably narrower than the HD599 SE and I think they had no slam to them or fun factor. They’re like HD6xx but slightly worse and barely have a wide soundstage but that’s just my casual opinion. I know they’re quite loved headphones. I don’t know how but the HD599’s have magic to them lol or I’m brainwashed at this point.
Seems like you’re missing the sony mdr-7506/v6. They can be driven hard and they’re pretty accurate at every volume level. The only downside is the insanely long coily cable. But given the list you’ve compiled I’m assuming the Sonys were on your list of headphones to consider at some point. At $99 and $79 on sale most of the time I think the MDRs are overlooked by few but known by many.