Anyone? What do you suggest for the table top?

Flowers.

Keep it simple, huh? Okay.

I think an interesting area rug with a bold pattern and perhaps a more dramatic wall color will give you the look you're going for. Everything you have in your DR so far is very lovely, you just need a little oomph.

Your room is very Zen. Resist the temptation to overdecorate.
A piece of driftwood on the table or simple low vase of flowers.
You could change the dark curtains to a light subtle textured fabric.
Lovely room.

I'd transfer the sideboard pottery grouping to the centre of the dining table. A beautiful long, narrow, sculptural bowl (wood, ceramic, metal or glass) would fill up some of the sideboard's surface area but not compete with the botanical prints, which are pretty busy. There are a lot of long, strong, rectangular shapes in this room. Maybe create some balance with a substantially vertical floor plant? I also agree with the previous comment on the drapes being a bit heavy in visual weight.

Are you totally committed to the chandelier? In the picture it seems to dominate the room. It's open indesign, but it seems almost as big as the table. Something less rectangular and bulky might help. I'd be tempted to try a couple of striking pendant lights instead.

I think you have a lovely room and agree very much with gustatruygers observations and suggestions.

I would add that a print or painting above the table in the corner may be a nice addition. Perhaps something that references the botanical theme above the sideboard.

You could also consider a runner on the buffet with a couple of buffet lamps such as below:

Likewise, candlelight is always nice in the dining room. You could consider some candlesticks or pillars on the buffet as well.

You could even consider sconces:

Crisp white table runner with flowers in the center. Flowers similar to those in your pics...not colorful. I wouldn't put anything on your buffet except what you already have.
If you end up saying you want something on buffet, you'd have to remove the outer column of photos from both sides and then you'd be free to put some tall table lamps.

Or if you don't want lamps, sconces or even tall plants would work.
But I think it's fine as is right now w art and only the small jars on the buffet.

Consider an exotic sculptural very vertical bit of lighting for the corners

Make your art personal and dramatic.

Oh and ps you wanted visuals so here you go lol.

I agree that the chandelier takes up too much of the space and doesn't really help. A nice, smaller scale light fixture, lighter curtains and an oomph of color in your buffet table (think table runner and fruits) will do magic.

Long and low on sideboard. Possibly clear glass candlesticks.

Lighter drapes in neutral tone.

I find the art hung too high and I do not like the chandelier at all or the dark drapes I love the pic from nmp19 and fresh flowers are always my go to in a space like this they cost next to nothing at the super market and add so much to a room I buy them all the time . I love the idea of a long low piece of driftwood on the buffet and if there is a blue in the art work I think i would paint that wall a pale blue

Art could be hung a bit lower.

I would select a long wooden trough for your table and fill it with faux osage oranges or succulents. I like the very spare appearance of the room.