Gosh, not a single comment in a day. Should I take that as a good sign?

The concept sketch shows traditional cabinetry on right and contemporary look around fireplace. Not a good idea. I would keep the material on the wall consistent across that wall. It will look better. Horizontal lines are good look with either shelving or stonework.

Sounds like you know enough about home performance that fireplaces don't belong in efficient homes. Gas inserts are just as problematic. A free standing woodstove makes the most sense from a functional point of view but even those are suspect unless you live in area of frequent outages or love heating with wood and don't mind the indoor air quality concerns.

Flo, I like that last idea most. I want to try to keep the cabinetry there, and it will be that traditional style if it is. But maybe I'll have to change it up. I'll need somewhere to store equipment, but I think I can get clever and have storage above the fireplace itself.
I found this photo yesterday I quite liked that seems like it could fit my homes aesthetic.

Brian/Springtime Builders, yes, our company is labeled 'home performance services', so we better know our stuff!
This will be a 100% electric home, and the fireplace for backup was my fathers idea for that power outage anxiety which I just don't feel is justified where we are, or with a super efficient house.
I submitted my plans yesterday calling for a propane FP, and the building dept. would've needed a permit for it. That extra bit of paperwork was all I needed to say forget the whole thing, we'll put an electric one in and buy a backup generator for the house with the savings.

Good plan. You can use stone on one side but paint cabinetry dame color fir unified look. Keep styling same too.

We are looking at doing this by moving our fireplace off to the side and putting the TV next to it. I have a bunch of inspiration pictures in my idea books if you want to take a look. One thing that seems pretty consistent is to extend the hearth under both to unify them. I am partial to the asymmetric designs.

I really want to do an electric fireplace with glass rocks and LED lighting. We don't need the heat from a gas fireplace but I worry about resale. In our house with southern exposure/passive solar design and radiant floor heat we (and probably everyone else) would never need the heat from a gas fireplace because the warm floors keep you toasty. Decisions, decisions...

I think you can do the fireplace on the left and then extend both a hearth across the whole space along with perhaps a mantel or shelfs across making sure your TV will fit into the spaces. Might take some work to get the measurements and balance just right, but it can work well.