I would suggest a much larger and more colorful rug for the sitting area. Your TV setup looks awkward and unattractive. Can it be changed somehow? I would paint the brick wall in the dining room the same color as the other walls to open up the whole space. I would remove that large mirror and put a smaller painting there and also remove the tall bookcase(?) near the couch which adds nothing to the decor. The mantle should be cleared and some much larger items placed there. I don't know how you feel about painting the fireplace the same color as the wall, but that would also make the room look more cohesive and spacious. I'm afraid the ceiling lamp by the front door looks too small and droopy to have any impact. You need something much larger that has a greater presence. Another thing to consider is white blinds instead of brown ones on each side of the fireplace. Again this will open up the room. I would remove that small table to the right of the TV with the little lamp and put a great-looking floor lamp there. Is there some way you can do without the bulky ottoman? I think that's one reason that area looks so crowded. I would think about replacing it with a small but sturdy glass and metal coffee table through which you can see the rug, giving the illusion that there is almost nothing there. Hope I haven't overloaded you with too many ideas. It's your home and you can do whatever seems right to you. If you follow even a few suggestions you might find that some of your concerns are removed.

I'm afraid it will not look like your inspiration picture, where the space has more grandeur and, frankly, the chairs are more interesting. My first thought was also to combine your table with modern chairs. And I'm wondering why the interior designers you mentioned told you to go transitional instead of modern.

Maybe it's my clumsiness but I'd want something fairly shallow on that wall if I needed storage (15" deep or less). Otherwise, colour can "fill" a wall. A mural or art as mentioned above would be fun options. My first thought was a row of étagères with interesting details. Perfect spot for coffee table books and some interesting objects. Can get pricey as an option though. And I'd need to "curate" the display, otherwise it could easily look cluttered. A low-budget option could be a graphic wall created with paint. There are even some geometric wall stencils for this purpose. Plenty of options out there! Have fun with it and hope you keep us posted.

jennifer, if you want to do a slat wood wall (there are a lot of tutorials on how to do it. it's mainly 1x1 or 1x2 wood 'sticks' that are 8'-10' tall. you could use fir and stain them. or you could paint them black. or, if you have a bigger budget, get walnut or something similar. walnut you'd only have to oil. it's a red wood. just a medium brown tone that would great w/the floors. if you like a more natural color, look at 1x2 white oak pieces. (any lumber place should have them) a satin oil finish is all you would need. those can also be stained a walnut color. (oak is cheaper than natural walnut this one is actually poplar that they painted. if you're goign to paint, use poplar wood https://brepurposed.porch.com/2020/01/20/diy-wood-slat-walls/ so, you'd paint the wall black, and attatch the slats. this looks like Alder that has been stained a darker walnut stain. here's the lighter stain color. you could also get plywood and rip it to 1" pieces (however, plywood and lumber have skyrocketed this last year. it's ridiculous what a sheet of plywood costs.) https://simplyalignedhome.com/affordable-slat-wall/ I think if you even did the entry niche w/some type of slat or design would look great I'd go all the way down, and prop paint it black, or do the wall in black and do walnut wood pieces. or, I like this too. find a cool black/white/gray piece of art, something more vertical, and hang it. bring in some bright color stools to fit under the marble. bring in a entry way rug that matches or make a cool design and use that as your art element in the niche (I actually made a headboard similar to this one out of scrap wood pieces. came out really cool) over on the dining wall, you could easily do a living plant wall