The V90 indeed slightly more v shape than ZSX but not by much. ZSX have forwarded mids and more musical, more balanced overall while V90 indeed sounds smoother, with more textured bass, slightly clearer overall, with more high emphasized.
To date, I still cant mention which one are better, they are really on par / tie just with different pros and cons.
@darmanastartes Nice review brother, I heard mostly similar to your review even with comparison with BLON BL-03 and V90, except on sound separation and micro details part, I heard ZSX has better one, by close margin. Some details in tracks more easily heard in ZSX but presentation in V90 is smoother. Good job and thanks for the graphs.
Btw i modded my ZSX a little bit, with very soft density foam, as a damper, very thin one. Made the ZSX less edgy now without losing details.