I would knock off the mantle for a flush finish.

look into a over fireplace TV mounting bracket

it pulls down for a better viewing angle. (when not using fireplace)

Thank you! - our contractor suggested replacing the mantle ( two layers of brick - with a reclaimed wood mantle ) to buy some space above - just not sure of the resulting overall ratio of it will look off.

We just redid our kitchen a year ago (white, transitional aesthetic) and ended up doing our fireplace that is directly opposite it as well. We love how it turned out. We removed the large hearth, put a beautiful tile on the floor in place that blends with the new flooring. It saved a lot of space and looks much cleaner. The front is tiled with 4 large tiles. Yours seems to have a similar size and shape. You might like what we did. The mantel was custom made by our contractor but is an incredibly simple. See photo. All I had on my phone was a Christmas photo. I included a photo of our kitchen so you can see the look. don't laugh at the kitchen table. Our kids are still in the destructive phase so we haven't replaced it.

Thank you Shelly - your kitchen came out beautiful - and I do like the new fireplace look too - did you have to move/replace the whole fire box or did that stay as is ? I feel like our hearth is so high it might force us to move or replace the firebox too ( which I would like to avoid if possible )

We kept the same firebox in the same location. Yours seems to be a bit higher than ours. You will want to see what code is for anything installed over the firebox. You may be able to move your mantle lower than it currently is. That would buy you some space. The other option that we considered, and you seem to be considering is not having a mantle. If you do full stone (stacked or boulder) you wouldn't need a mantle. You still need to consider code though in terms of how close to the firebox your tv could be mounted. As it doesn't stick out too far, you may not have to worry. May be further out depending on the mount you choose. You wouldn't want to damage the tv..

Thanks again - yea - thinking of The Frame TV from Samsung - it mounts virtually flush to the wall and looks like a picture frame so I think we will be ok ( but still need to research this). Ideally we would keep the brick but lower/replace the mantle to buy more space - all good input thanks !

You might consider something like one of these with the material and colors that suit your taste.  I think it would make the fireplace a nice full feature, update the look without having to redo the box and not make the area above look so short.