Take that heavy mirror down and STORE it or sell it. That's the first thing.

Nobody can advise a rig beyond the size. What style? What are the other rooms in style? Even a dining room does not live in isolation, separate from all else:)

Window covering will add some softness & warmth!

hang a painting or family portraits on wall above cabinet & between windows if you wish to. Images that is close to your heart will make it special..

Thank you! What type of window coverings? Drapes or blinds?

I agree with Jan, IMO the mirror overwhelms the space. As far as window treatments, drapes are soft and would be in keeping with the style of your furniture. I have a pair of antique buffet lamps on my buffet (look like crystal candlesticks with brass bases) along with a much loved pale blue Chinese war horse statue and an antique brass and blue tin. You could get a painting and sit it on the buffet instead of hanging, then add some side interest. It just depends upon what you like. Have fun with it, you can always swap out pieces!

Thanks. The mirror is sentimental, so I’d really like to keep it :/

following

Is your table centered under the light fixture? It’s hard to tell from the photos. If not, I would start there. The rug markings look smooshed to one end of the room.

you could mix modern and antique. Some inspiration:

Not a Pro.

Above the buffet place a piece of beautiful art in colors you love! It will be reflected in the mirror. Use those colors to find an area rug. I would sheers on the window and keep it light and airy.

Please post pics of whatever you decide.