Hello Paul.
The room acoustics overlays and imprints your audio experience. Some "upgrades" that a person can hear are merely an effect that penetrates the acoustic noise floor. Some upgrades are real and you'd love them if only you could hear them, but they lie buried below the room acoustic noise floor. As I read your list of equipment I didn't see the acoustic compliment you are running.
A good system performance experience is to download and listen to the ASC MATT test (musical articulation test tones). https://www.acousticsciences.com/matt
Listen first over headphones, kinda boring, then listen to your system play the test track.
The test will speak for itself.
Sincerely, Art Noxon
ASC