Sound quality issues streaming from Tidal vs CD

I am hoping someone familiar with streaming from Tidal might be able to help.

I have recently installed the Pro-Ject Streambox S2 Ultra, which is a small Raspberry Pi based network bridge. I connect this to my router via ethernet cable and to my Vitus DAC (which is part of the CD player) via USB. My CD player obviously outputs through the same DAC.

The sound quality from CD is so much better than the sound quality from Tidal (I am a Tidal Hifi subscriber).

So my questions are:

1. Is this just a feature of streaming via the internet, it simply is not as good as a good quality CD transport?
2. Or is it an issue with the Pro-Ject - would something like the Autralic Aries G2 (also a network bridge with no DAC) which costs 6 times the price of the Pro-Ject, improve the Tidal stream?
3. Or is it the fact that the USB cable I am using is an entry-level £10 cable?
4. Or is it Tidal? - would Qobuz sound better?

Any advice or knowledge would be welcome.