Why did you not simply remove the shelving? I don't understand, was it to get electrical in? seems better ways to have done that.........

Are the pictures yours or SIMILAR TO yours? Get a trim carpenter, take off all the existing crown molding, Get new molding for the entire length, plan to RETURN it to the wall above tv , OR DO A PANEL, and line up the bottom with an adjacent shelf above you do not want the look of a valance.

Frankly, the arches make the whole feel rather dated...I'd have those gone. Really a trim carpenter would be worth your money

The shelves are all too close, remove/re space to an odd number with more space - too cluttered.

This layout might be complementary to what you already have.

I would put the shelves and moulding back, just remove the lower shelf, no need to mount the TV on the wall, just set it on a stand and move it forward, to the edge of the cabinet (the speaker is in the back, you'll muffle the sound by tucking it into the box)

Have you considered painting the whole wall and cabinet a dark color? SW Oak Leaf Brown, SW Naval, a little drama and a dark background to show off decor on shelves?

I would have just removed the shelves until I had a plan re: what I wanted the wall to look like when finished.

If you are going to update the wall (as Jan has suggested) - think about how much room you leave in the center for the TV. TVs are already larger than 65" - and you don't want to wind up with a space that is too small in a few years.

I am hoping you saved what was demoed and that it isnt ruined, because the original top is what needs to go back there, and maybe 1 or 2 of the shelves too. Anything else will not look nearly as good.