The advice to change caps can be ignored at this stage. I am big into the improvement caps can make but you need to get system balance first.
Cables, vibration control, etc. all help and in some cases make huge differences and those too are for experimenting with after the system is performing to the point where you are enjoying it.
There have been suggestions to change the pre-amp which I agree with but, again, later, after, after what?
Your room. You have not described your room nor mentioned if you have any room treatments. I suspect you don’t.
This is important: You will have no happiness unless you treat the room, FACT!
People in the main simply can not conceptualise the importance and effect it has. I can assure you that a system worth 1/3 of yours in a correctly treated room will outperform it to the point your jaw will hit the floor. It was suggested you move the speakers. To prove my point leave the speakers where they are for now and go stand in a solid corner at the back wall and you will hear bass. Big B&W have bass and you are probably sitting in a null. Null? ... look it up.
A DBA will also help with smoothing out peaks and nulls which not only cleans up bass but mids and tops as well. True story.
Consider why you have been asked more than once to describe or post pics of your room. Does this not ring alarm bells that acoustics may be important? It is more than that, it is the sole determinant of good sound.