Answer: use refractory brick, aerated concrete slabs or steel wall protection panels.
Several effective and aesthetic solutions exist to protect a wall behind your stove. The firebrick will give your garden area a little garden air. Cellular concrete slabs lend themselves well to contemporary interiors, while insulating perfectly with fire-fighting properties. They can in particular be covered with technical paint with high thermal resistance. There are also steel wall protection panels, including a layer of thermal insulation on the wall side, which prevent the darkening of your walls. This type of product is sometimes offered by manufacturers and installers of stoves. Also note that a minimum distance between the stove and a wall is mandatory and varies depending on the size and model of your stove.