I've run various cars over the last 25 years, and have never done anything special to protect alloy wheels. Never had any issues either, and I take wheels off a couple of times a year to clean them thoroughly. Alloys have a clear lacquer coat on the (usually) painted wheel, so unless a wheel has got gouges in it, then there is no reason why it would be any more susceptible to damage than any other part of the body, and probably a lot less, as it doesn't contain steel, which will just rust through.

Chromed wheels are a different matter entirely though, I'll accept.

Finally, if you have a really careful read of the various 'winter doom' articles, then you'll see just how vaguely they are written. One a couple of weeks ago said words to the extent of 'any areas of the UK could see heavy snowfalls and below freezing temperatures in the next 3 months' ... yes, it's called 'winter'.

You might consider using PlastiDip, as I have read some others have done. Clearly though don't spray the wheels while still on the car as some YouTube videos show; that's fine for appearance in California but it's not the anti-salt protection you are after. I haven't done this myself, I have a set of (allegedly) winter alloys for my winter tyres. Must think about dusting them off soon...

As others have said, alloys will probably be fine with the salt. Things like stone chips are probably more likely to be a problem.

You can get wheel wax which makes the wheels easier to clean and should also help protect against salt.

The only corrosion problem I've had with alloys is sticking to the hubs. I put some moly grease on it (just on the bit that makes contact, not the whole wheel) to prevent this.