which iem/dap are you gonna use it with ?
i think
EA Lionheart ticks all these boxes in bold, i used it with my Zeus XR and i got a more lush sound without killing Zeus' amazing transparency
PW 1960s 2-wire is also a great cable and the one i currently use with my Zeus XR - such amazing clarity (without sounding clinical) and the lows gets a big boost, but it won't smooth out the treble as you want - plus it also costs double the money (1000$ new to LH's 500$)
but again , most important thing is again synergy - more expensive does not always mean better