I probably need to return it too, but in my country, unfortunately, nothing can be returned without numerous courts.
Xduoo support takes several months to respond.
p.s. This is what they just answered
Hi,
If you use high-sensitivity in-ear earplugs, there is a slight white noise, which is normal, because XD05PRO has high output power, its minimum gain (ECO), and also has 12DB (unbalanced) / 16DB (balanced) output.
If you only drive high-sensitivity in-ear earplugs and do not need so much outpower, you can reduce the gain of amplifier, that is, by changing several resistance values on the ear amplifier card, you can reduce the noise, as follows:
Change 2KΩ to 1KΩ value