Firebox question

[Rlips]

Our 1980’s home came with a wood burning fireplace that had been converted to gas. We removed the gas, and had the chimney inspected. Everything was “good” but I still have some concerns that they just shrugged off. The fireplace is far from weather proof. In the winter cold air blows out of it and in the summer when it is very hot and humid we occasionally get condensation on the glass. There is a gap between the stone and the metal firebox all the way around. Could it be filled in somehow? It is additionally a great way for bugs to get into our home 🙃.
Lastly, could brick be installed over the metal firebox, insulating, and covering those gaps? I’d love the firebox look of the last 3 photos. I have no knowledge of fireplaces as this is the first home I’ve ever owned. Any advice or help greatly appreciated!

 

[stoveliker]

There are balloon-like pipe "clogs" that you can put in the flue above the fireplace when it's not in use. Blow it up, it takes the shape of the flue and blocks air flows.
If you are intent on keeping it a wood fireplace for ambiance, that's what I would do.

Another option (you're on a stove-addict forum here .. ) is to put in an insert. But that's a different beast altogether.