No single product works well on all surfaces and situations. The Boeshield T9 works well on the types of surfaces it is intended for. CRC has a Corrosion Inhibitor as well and also LPS and they also do well on many things.
The steps are usually painted or powder-coated anyway, so should be fine as long as the surface is intact. If it gets scratched, touch up with paint to continue the protection. That will be far superior to any anti-corrosion spray. If already rusty, clean with a wire brush first. Use a rust converter such as Ospho if rust is more than a surface film.
Pivot pins and such can be protected with Kwikee Kwik Lube, which was originally designed for Kwikee brand steps but is a great general dry-type lubricant. It is widely available now.
https://www.rvautoparts.com/Kwikee-A...000_p_639.html
Plain old dry silicone lubes work well on many things and they are inexpensive.