I can say that unbalanced outputs from a USB device can be reason for ground loops if using a Desktop computer and mains grounded powered speakers/amplifier(s).
A lot of consumer HiFi amplifiers are now double-insulated and so do not have a mains earth/ground, so it doesn't matter. If using a laptop with 2-pin AC-DC PSU, then it won't have a ground either, so no ground loop.
For what it's worth, in terms of a non-blind listening test comparing the Topping D10 (from Laptop) to a £400 CD player, once the level was matched (+gain [64 bit floating-point > 24 bit w.TPDF dither] on the Topping) they were as good as indistinguishable!
I say a non-blind listening test, but bear in mind we are going to want something that cost some cash to actually outperform something that didn't. Jaw dropping moment! Bought a second D10 straight away.
I'd imagine the Khadas Tone Board sounds just as good/maybe better, but doesn't have a case.
My mind tends to wonder what does buying the next model up, and then the next above that, of the international branded CD player get? Is it all just BS and a slight tweak of gain? After all a small change of about 0.2dB will be felt as body/thickness/richness but not heard as a level/gain difference. For us to perceive a volume/gain difference, the difference has to be around 0.5dB or more usually.
I need to buy an recording interface, but for a new output interface I'd be looking for internal isolation via putting the USB chip on one side and sending a IIS (I2S) signal over an isolated boundary and some thought and planning with regard to reducing jitter produced from this isolation. That and/or balanced outputs.
Ground loops are a pain!
At least, at the time I bought it, the Topping D10 was fulfilled by Amazon in UK, so an easy purchase and warranty is handled without much fuss. Importing adds customs duty and a potential nightmare for warranty claims (shipping back/waiting).
All the best on your choice of purchase.