i’d like to hear what the DAC is, and what apps you are using on the Apple unit, whether you are going bitperfect, and how you are isolating your USB from the computer’s noise. If for example, you use the computer’s digital volume control you can be down in 10-12 but resolution very quickly. Settings matter too - from the basics to more esoteric stuff. Computer audio sadly demands some new learning. Only then can we begin to comment. Absent that its guessing or pontificating.
Absent facts id; say no that is not expected. But then, what kind of sound do you liek and does the DAC tend that way (detail vs smooth, blah blah).
To many who said "no surprise they sound the same at that price" - he said the opposite. Which is curious. there are of course lousy $300 Dacs. Some that get good reviews are, IMO, kinda analytical adn nasty.