Check out Besta from Ikea

Try mounting the TV on the wall and then hanging the artwork next to it.

Pied-à-Terre: Family Room · More Info

Financiers Pied-à-Terre: Hallway · More Info

Wooden wall shelves like these would fill it up nicely

I like Darci’s idea of mounting it on the wall and hanging artwork to the sides around it. Then reduce the clutter on the cabinet to have a clean, classic look. Your cabinet must be functioning fine (or you would have mentioned it) and i don’t think buying something from Ikea just to buy something makes sense, or is necessary. I suppose the shelves would also be a good idea if you want to display a collection of some sort, but you’ve got a good start for a clean, polished room