No problems with wood on my wood boat above the waterline and any SS screws.
Wood is not wet enough unless it is submerged to damage SS screws. I speak from empirical experience and replacing many thousands of screws in wood. I rescrewed my teak deck using SS deck screws 18-8 from Home Depot years ago and they are perfect. I have even pulled some out to see. That teak deck is screwed onto 2x4 beams. I also completely removed every bottom plank on the hull, re screwed with 4000 number 2 square drive bronze screws from McFeeley's. I have owned this boat since 1998 and done lot of work on it.
I have these 2 teak stair steps on both sides of the aft deck. They have bronze angles and SS screws were used to attach to the teak. I recently pulled them out to redo the teak finish and they were again perfect. Now those screws were put in before 1998 when I bought the boat.
My wood toerail, attached with big bronze screws or brass, many were corroded and broken. In 2000, I removed the toe rail, rebedded them and attached all using SS 18-8 3 inch long deck square drive deck screws. And the toerails have not budged. the wood is mahogany.
Thing is people who build decks, is just like boat decks, and SS screws work great in the rain and corrosive arsenic treated wood.
Go to the wooden boat forum and ask them if SS screws are fine above the waterline, and you will find they say yes.
I did some plank work on the hull above the water line. And most of the bronze screws were corroded and many stuck tight in the oak frames. They were still strong enough as is, except for the but blocks where most were wasted away.