wonderful room, only a few small tweaks, could really help. you do need a larger stand for your tv, can you pull it out of the corner and put it against the wall? either to the right of where it is cause i can't see there. or where the shelves are or where the chair is. i think you should pull the chair out anyway, not all your furniture needs to be against the wall. here are a couple ideas i would keep the cute little marshalls table and replace one of your side tables with it, it will give you a touch of variation. here are some other choices for coffee tables, i buy reasonable things, if you use your computer, you can hit the key and it will take you to the company. you seem averse to color, but white on black is too loud. let me try some other ones. put one on your chair and they will all match. i have others, and others in a different color if you like all should be under $25.

If this space does not need to be a tv room, I would take the opportunity to create a music/library space. Do a wall of built in bookshelves where the accent wall is and get four super comfy club chairs in either leather or velvet, a couple of ottomans, and a couple of end tables. You could group all four together in the middle of the space, or do two groupings, one closer to the piano.

@Lil S Sorry I was having trouble uploading the photos but I just added more.

Lots of ideas on Houzz photos ... I just searched "modern TV wall unit" in Photos and got 107,004 photos! Save the ones you like to your ideabooks.