Radiant Barrier Insulation

cdx plywood. You can find some with one side sanded. Be picky, you’ll find it. Stay away from osb and bare board. I would not use Masonite either.
I closed cell spray foamed my new shop 40X54 and put 7/16 OSB on the walls and the ceiling. Painted the OSB with two coats of outdoor latex paint and never looked back. The OSB shows zero signs of degradation from moisture.
I will never put up another stucture without spray foam for insulation, that stuff is amazing. Energy efficient, moisture barrier and sound proofing all in one application. Well worth the money spent.