text: You are quite right. Unfortunately there seems to be no other way to tag this place (tourism=gallery would not be approriate). See even the sculptor-park att Hunnebostrand (https://www.openstreetmap.org/way/58381936). By the way, they are shifting the sculptures - at least some of them - occasionally. I'll try to attatch tag tourism=artwork, but cannot say if this will be ok. I'll give it a try. Thanks for your comment!