One thing is for sure, we all have opinions. Some cables can be a bad match, but I do not think they are the problem. System synergy is very important, it is clear that you have some very good gear, but maybe they are not a good match for each other. Furthermore, from what I have READ, no experience, the speakers you have may not be the best for the music you like to listen to.
The headphone idea is good if possible, but also if you have access to other gear, swap out pieces until you find something that may be the cause for lack of synergy.
The headphone idea is good if possible, but also if you have access to other gear, swap out pieces until you find something that may be the cause for lack of synergy.