Since both your DAC and amp should be completely transparent, the first thing I'll recommend is seeing if the headphones are the problem. If the sound is too edgy for you it might be because they have too much treble for your liking. If so, changing to a different audibly transparent DAC will do nothing (expect padding the bank account of whomever sold it to you…).
In your place I would first play around with EQ to see if there is an offending frequency range that by lowering it you will get a "smoother"-feeling sound. Or maybe switch to a different headphone with less "edge". I couldn't find a trustworthy measurement of these headphones, so I don’t know if they actually have treble issues.
If you say that the Arya sounds better to you on another DAC, you should try blind testing to see if you can really tell apart how it sounds on a different DAC. If it's a transparent DAC like the one you have, you shouldn't be able to notice the difference, and that will be a good demonstration of the futility of DAC upgrades.