Yes, that is likely, the coordinates and how warped they are is pretty evident in that image too, it is that view space that you'd likely want to correct, but not just for the one shader material but probably for your whole scene render, hence my original link in my first reply.
Simple solution might be to just render your scene to a viewport(rendertarget) and apply a counter warp to it.
Once you have successfully corrected that you might find it much easier to achieve your actual goal here which I'm guessing is to get a billboard shader that tracks the camera outputs center more closely?
One fair point on that note, should you try to utilize that in XR or any form of stereoscopy it will be problematic: each eye would have it's own dedicated camera/view and be offset from the other.
Not that any sort of billboard would work well in that situation, tbf.
