IMO Auralic is a step below some of the other usual suspects (Innuous, Lumin, and Aurender). I personally would upgrade my streamer first, and see how you like it with the Gustard. You’ll have a world class streamer, and can always upgrade the DAC if you find the combo lacking…..as funds permit. See if you can demo a couple of units if a dealer near you will permit.
I borrowed an Aurender from a friend, and holy crap….it was magical paired with a Denafrips Pontus II DAC. I’ve heard Lumin and Innuous in friend’s systems and they sounded amazing, but never in my own system. Also the Aurender app to be excellent, on par with Bluesound’s app