Yes. I think a thick wood mantle would add a lot of texture.
I’d go for a French country vibe…

It's a lovely fireplace, but it "blends" too much. What I'd do:

-Definitely yes to a mantle. Somethng substantial in a wood tone to match the floor.

- Do you have to hang the TV over the fireplace? Do you have any other options?

- Add some drapes to the windows ... again, bring in color.

- Don't neglect the door, as it needs to tie in with the windows.

- Add a few bright pillows, a basket or some type of artwork to the base of the fireplace ... again, with color.