What does playing with router settings accomplish when certain tracks not playing from Qobuz?
As others have noted: DNS setting. Also, for those using Comcast ("Xfinity"), I recommend ditching all of its equipment in favor of buying your own modem and router. I've done that and have no issues with Qobuz.
One issue Qobuz and its competitors have is that labels and distributors periodically remove files, or replace them with other files that have different paths. Naturally that causes an issue when you're using a saved playlist.

