Great you got sorted. I am actually not surprised that you perceive an improved SQ with a fully functioning unit. I have had similar experience with a repair that resulted in perceived better SQ. In theory, it shouldn't have made a difference but it did. And quite a significant difference too.

My theory is either:

1) the malfunction of a part can have an impact on the performance of a system. And when that malfunction is rectified the impact on other parts of the system is resolved. Think of a misbehaving ID41 that was emitting more noise than usual or actually directly polluting a signal caused by a dodgy cap, chip or resister. Fix that and we can easily understand how that may result in better SQ.

My example was an intermittent volume change in one of my DSP. Ultimately resolved at HQ. SQ on return was significantly better. I actually had to ask whether something more fundamental was changed they were so much better. No expectation bias here. I was not upgrading or trying to justify a purchase or testing a new gadget. I was not expecting any change other than the issue being fixed.

2) the listener is so damn happy that it is working that the joy translates psychologically into a better listening experience.

Or both 1) and 2)

PS
agree that network issue are 99% of the issues in most user cases.

Rgds,
Nick