Since 2015, all direct vent fireplaces sold in the USA are equipped with a safety barrier of some sort to prevent the exact thing you have described. Having said that, the non-combustible surround of marble, granite, or other material can still get very hot and may cause injury. You are in the the minority of folks that think their fireplace provides too much heat, but there are quite a few of you out there. There are a couple ways around that. Some fireplaces, particularly those designed for big commercial applications, are very safe and produce very little heat. Check these out: Davinci The other option is to go with an electric fireplace. Some are very realistic: Dimplex Opti-V There may have been enough technological improvement in regular gas fireplace that you will be happy with a basic, low BTU (heat) gas model, but you have some options.

I'd have to see more of the space, but my general advice would be: Don't mount a TV over a fireplace.

I would remove the existing pillars and mantel, they look too crowded against the windows. I would install a clean and simple modern tile around the fireplace. I think you could pull off the TV mounted once you get the pillars and mantel out, install a lower ledge to help protect the TV from the heat of the working fireplace. Lowering the ledge/mantel and with today's TV mounts should allow the TV to be positioned easier for viewing. Do your research on TV mounts, most of todays TV's are super light but block for it in the wall if necessary, particularly if you think you will be moving t he arm mount around often. You will get your depth from the TV and the ledge mantel so dont worry about creating more with trims and moldings. Best of luck!

one huge advantage of having a fireplace that low is that you can hang the TV above it and it won't be too high. I like the idea of adding drywall to close the wall in, adding storage on the back (facing the hallway). you could use one of the existing nooks to store firewood. add shelving to the other for media consoles, books or decor. you could always drywall over the nooks too.