In terms of the imaging and soundstage on the Audeze LCD GX, I think overall it's excellent. While the soundstage isn't as wide as other headphones that I own, specifically the Philips Fidelio XR2 is wider, I feel that the detail and seperation go far beyond the Fidelio which is crucial when picking up several sounds in a wider soundscape.
In terms of imaging I often read a lot of comments in reviews and whatnot which seem quite baseless in terms of headphones. I don't have a good understanding of how imaging is measured, but what I do know, is that I can isolate the direction of players fairly precisely on Apex Legends. For me the mark of a excellent imaging and soundstage is where I can
a) Identify the direction an enemy is coming from
b) Approximate the distance an enemy is coming from
If this works out well, the ideal scenario is that I can actually aim with audio rather than sight, so I can pre-aim an angle or even turn and snap onto a target as a result of the sound.
You can see this play out effectively here in this clip at the 51 second mark.
The first player opens one of the large doors behind me, instantly I know not only that he's behind me, but which door he opened and I pre-aim the right side of my doorway ready for him to approach. I then hear footsteps on the left side door and turn to face that way. They stop for a moment and I turn away because I thought that meant she was walking away or took a different route, but then the footsteps pick up and I turn to shoot her accurately as she comes through the door (and then I miss a load of shots and almost die but that's on me).
In this regard I think they're the best headphones I own for multiplayer shooters. If I can reliably and accurately ready my aim through audio then that's the advantage I want out of them in that space.
The only other open backs I own for this are the Philips Fidelio XR2 and they have a wider soundstage but they are more warm sounding and the separation is less good so things get lost in the mix more often. The LCD GX is actually the first headphone I have owned where I can play my music (quietly) while playing the game and not have that significantly negatively affect my ability to tell what's going on.