If anyone is looking for this, here is the color code for the wires once you cut off the 3.5mm single-end plug:
White - L+
Green - L-
Red - R+
Black - R-
Unless you have already got that dongle, I'd recommend Hidizs S9. DC03 got nasty multitone noise at 0 dbFS. https://www.l7audiolab.com/f/measurement-of-ibasso-dc-03/
@amirm can you make a post on how do you create EQ for any headphone? I understand the end results are largely personal taste, but it would be very valuable to know how do you make those choices. Do you adjust EQ based on the FR curve? Many thanks!