I have had a wood-burning stove with 7 kW in a living room of about 40 m² for years. The door to the hallway is always open, not for heating purposes but because we like it that way. It largely depends on the heating behavior. I heat exclusively with wood from my own forest and save about 25 - 30% on heating costs. The stove with 7 kW is oversized. I easily achieve over 40 degrees room temperature. On the other hand, I only have to add a few logs, and it is great. Side effect: the humidity decreases. There are also specialist shops near you, get advice there.