I have now clad the wall in the living room with Stone Design Luberon from Bauhaus. It looks really good. However, they are not suitable for the bathroom, as it is an imitation made of gypsum or something similar. With craftsmanship skills and enough time, it is no problem. It just creates a lot of mess. I mainly decided against tiles because of the chimney and the fireplace connection in the wall, and I also couldn’t find any samples of the tiles nearby, and I don’t always trust photos. It is definitely not a job for just one weekend, although maybe for a small wall it could be. But I would still let the adhesive dry for a few days before grouting. The price for about 18m² of wall surface was around 600 € (material and tools).