Beautiful space and love the stone.
Personally will not do osb walls again as I don't like how it looks when painted and the gallons of paint it soaks up seems to negate any savings(from back before prices went crazy)
If I was doing it again in a detached space I would probably be looking at a mix of metal wall panel down low, plywood for the areas where I anticipated hanging more items and drywall everywhere else for a stick framed building. If it was red iron where blocking isn't as plentiful compared to stick built I might consider putting osb under drywall or adding blocking before covering things up.
Again just my preference, lots of great looking and functional osb covered walls in here
