More pics of the other side of the room would help.

I would recommend a large piece of art on each side of the opening (you can DIY), and 2 or 3 pieces over the sofa. Or you could flank the opening with a small cabinet on each side with floating shelves above. One could act as a bar.

What about a low bookshelf or table/cabinet with art or a mirror above?

Is that the entry door around corner in right side of 1st & 3rd pictures? I think if a piece of furniture is placed there it might be too crowded to place another piece at right side of bar counter. But, the inside corner on the left seems a great place for a cabinet almost the width of the space & art above. I wouldn’t have a tall cabinet there. I think it would make the left bar stool feel boxed in. Are you planning to hang art above the sofa? That’s what looks bare IMO. You’re not asking about area rug but I suggest pulling it away from wall behind sofa a bit so more of it shows & the nice red swivel chair sits more on it. Looks like there’s enough room behind the bar stools to do that.

How about a tree on one side and a fun colorful piece of art on the other? Window panels would look nice too.

You are a Pro?

Either a large plant as okibujp suggests or a shallow console table on hairpin legs with interesting thrift shop mirror above. (Etsy is a good source for custom tables like this that aren't too pricey.)

This one is $70 on Etsy. Shelf and hairpin legs customizable to size.

On right side, a great art poster in colors and subject you like.

P.S. Keep your countertop completely clear 24/7--more important than decorating side walls.

Wallpaper!

Paint. Then decide. Not all walls need art.