Yes for rug!

What is happening with those white cupboards? It definitely looks like something is missing or unfinished. Is there a way to make a connection between the items you have on that tv wall? The cabinet colour, style, or placement might need to be reconsidered. Adding a rug in the couch area will make that part cozy though.

What is happening here, please? Can you show the entire room from ALL angles? Begin at the front door? All the way around?

How about adding stone around the fireplace and then painting the entire wall, including the cabinets, a mid tone from the stones. Then a few paintings or art objects above the mantle.

Easy fixes: Adding a rug and complementary cushions and a larger coffee table if wanting to ground the seating area. Highly suggest looking at on line inspiration rooms to nail down a feel and importantly, what was used. The turquoise and burgundy feel a bit dated; consider warmer shades (if adjoining spaces suit).

Get a rug first to build from and other decisions will be easier.

This is a nice coffee table, is on sale and I think black is a good choice. If interested, measure to see if 48” works.

https://www.westelm.com/products/profile-living-room-collection-h6827/

I think the long wall feels awkward and unfortunately has such a big influence. I’d paint the cabinets (and fireplace?? trim) the same color as wall and use black hardware. I’d add a large basket/throw to fill the gap next to cabinets and adding black floating shelves on the sides of the tv will help ground that wall and add interest by taking away the focus on tv.

I would move the TV over the fireplace and then install artwork over the cabinets.

The wall colors in this room are not working so I painted the focus wall a deep gray to make the sectional more important.

I think painting the wall and adding a rug might be the easiest fix. What color deep grey? The color of the walls right now is accessible gray. Oh my God, Can I keep my coffee table and maybe paint it black?

Should I paint the trim the same color as the wall? I agree with changing the handles and staining them the same color as the mantle or changing out the handles for black ones.
I like having the TV centered. Maybe add artwork to either side?

Here is OP's prior thread showing where the white cabinets came from and what has been changed already.

https://www.gardenweb.com/discussions/6454252/fireplace-and-adjacent-wall-dilemma#n=12

The white cabinets are what stick out. Either mantel color or if you paint the wall a darker color, maybe wall color. I'd do large art on both sides of TV or art on one side with something tall on mantel on other side or a few shelves.

I agree, painting the wall sounds like the next step plus adding a rug.