IF your system is capable of sounding great on some tracks, bass/mids/highs and not others, it’s the fault of the recording, not your system.
musicians, placement of musicians in a space, specific mics used for individual instruments/voices, proper levels for original recording, all the mess of great/good/bad decisions by the engineers post recording, you are listening to the result of that mixed bag.
When it's great, my friend and I often look at each other and say "these guys knew what they were doing".
I don’t try to adjust anything to improve the track, EXCEPT, I love remote balance
to correct/improve imaging that is there but a bit off for who knows what reason. The more revealing your system becomes, you more readily hear a slight imbalance. A slight tweak of balance can make a surprising amount of improvement, not just the centered singer, but all players across the width of the stage are more distinct, sound and location.