We made the decision to mount light plywood on the wall in most rooms. We found an interesting 18mm thick coniferous plywood. It is nice and light, but heavy.
There was a question of how to attach it. We have a house made of veneer panels, some of the walls are beveled at a slope of just over 60 degrees.
What fasteners to use? Is there any experience of more or less inconspicuous fastening?
Consider attaching the plywood sheets to the finish stud without the air gun cap. It is practically not visible, there are different lengths and on a sloping wall to hold. I think 35mm will be enough to hold 18mm plywood.