I would do a search on "marine grade" door hardware and see what comes up. Some marine grade finishes require special cleaners for tarnish resistance.

Bad news, none of their finishes are guaranteed for salty air- not even the lifetime brass (there is a giant flashing asterix next to 'lifetime')

I have much more experience with Emtek. I've had their chrome and it had minimal pitting after eight years. I cleaned it periodically with 0000 steel wool, in hindsight maybe car wax would have helped. Looked good until I sold house. At my office I have their unlaquered brass, A year in it has lost its shine and is a dull 'antique brass' now.

I have used baldwin ORB and the finish wears off with time revealing the copper beneath- not pretty.

I am looking for something that does not change at all (stainless steel?), or something that is a solid metal that changes naturally with touch and salty air (but not rusting or pitting). Is the new white bronze a living/natural surface or does its rub off?? Do the nickel finishes rub off or rust/tarnish? I am not looking for the co-called Lifetime finishes- they are not solid metal all the way through and they have are a coating that will not last in salty air. I could apply wax to help prevent pitting or rusting, but which finishes are appropriate for that??