I put the TV on a separate wall than the wall which will eventually have a wood burning stove. (The mantle and backdrop is already in place. Right now I am dealing with homeowners insurance that doesn't want me to have one.) I don't watch much TV at all, and I really dislike - for me - having an ugly black box being the center of living room attention. When I have guests over, we're here to talk. I can think of exceedingly few occasions I'd be watching the idiot box with guests. Probably if they were here several days, we'd rent a movie or two via Amazon Prime. (Moot point right now, COVID and all.... but hopefully that won't last...) And with a wood burning stove, the exhaust pipe will go up and bisect the view of any TV over the mantle. I sat down on the couch to figure out the best viewing height - which is well below what the mantle might ever be, at least on this couch. It would be fine if I could lean back and rest my head, to have something over mantle height - assuming I'd go with a regular fireplace. But at six feet tall - there just isn't a couch or sofa like that. Plus as others have said, what about decorations? I enjoy decorating my mantle for various holidays! After all, that's really what mantles are for, right? The thing is off to the side, and it does not get glare there, either.

Like stated above, you need to be sure this is just one layer of decorative brick with just drywall behind it. If it is one of those fireplaces that the chimney is brick and all, you have a bigger issue. If just decorative, you will need something like we used to remove our faux rock. We got a little pneumatic attachment for our aircompressor. It lookes like a large screwdriver or mini jackhammer. Starting at top, you chizzle away. This is very time consuming but can easily be done. There will be lots of dust and debris. When all you have left is the studs, you simply put in new drywall. Again, this is all easy, but since this is a fireplace I am not sure what safety issues are involved like if you need specific materials on wall because it is a fireplace. My regular firebox just had drywall and so does my zero clearance. Also as stated above, there may be issues with what kind of mantle material you can safely use and at what distance from firebox. 12" is pretty standard but depends on mantle material. We lowered our mantle but we also brought firebox down to floor level. Rebuilding it was not that difficult. We simply built the legs, built the mantle and hooked them all up. The cost of redoing the brick is up to you. If you do the work it is just materials. But obviously hiring someone to do this will cost you. I would imagine mortaring brick is very time consuming because they are so little. But a seasoned professional can go pretty fast. But again, it will cost you. Sounds like what you want to do is doable and can vary in price depending on who does the work.

You will need to check with the manufacture of gas fireplace for the clearance they require. Removing the brick is not a problem, but maintaining clearance is essential. Check the manufacture and local code and go from there. A chimney sweep or mason who deals with a lot of fireplaces might be able to answer the questions also.

Is that a functioning fireplace? It appears to just have candles inside of it? If it is not a functioning fireplace, then mounting a TV above it, may not be bad if you can remove that mantle and mount TV a little lower. That's a small room to watch a TV mounted high on a wall. PLace TV above the shelf wooden cube shelf & have sofa float/face it. You can move sofa now & take pics to see if it seems too cramped. Or but a corner TV stand with a wall mounted TV you can pull out & angle when TV is being used. Or buy a smaller flat screen and mount on 32" wall & down the line, have built in made cooperating fireplace. If this is not the only TV viewing room, I would consider not using it for main TV viewing.