Stainless Steel is a great product for sure, but alas it has it's own set of problems to, I sail and all the metal fittings on the yacht are stainless or brass because of salt water corrosion.
Turnbuckles on mast rigging on our boat are stainless steel and ideally should be taken off every 6 months or so to help stop 'Galling' (Please see link below)
The magic Red Rubber Grease is the yachtsman's friend, the other friend is patience, don't be in a hurry, now this might sound silly but bear with me, spinning a nut fast down a stainless steel thread can generate incredibly high temperatures just at the apex points of both the thread, this high temperature is lost very quickly but is instantly regenerated by the next revolution of the nut or fastener and on the process goes eventually welding the nut to the bolt (or Turnbuckles in my case).
On the boat I use waterproof grease on the thread (Red Rubber) and slowly tighten the parts up (don't spin the nut down the thread at high speed)
Now you might be thinking tommy is yet again talking poo, the same process can take place on other metals aluminium being one of them, a form of Galling is often what will strip the threads out of your rear wheel hub when changing your rear disc.
Take a look at the link it makes good reading, that exact link changed my understanding on contact friction and galling weld.
Now I wonder why I am so opposed to LocTite on threads that go into alloy, as if they did not have enough struggles with out that being added to the frame. https://www.fastenal.com/content/feds/pdf/Article%20-%20Galling.pdf