Convert gas wall heater to inset fireplace
This is not a recommendation since I never bought or installed one of these. Try searching for Woodland Direct or phone at 844-312-5159. I searched on-line and found this site. They seem to have just about everything you could possibly want. They have for example, a Kingsman ZV3600 zero clearance B-Vent gas fireplace Item #3580119 that may work for you. They have a long list of other possibilities, Or you can look up "wall mounted gas heaters or fireplaces".