If I recall correctly, the NRA did some torture tests and concluded in their magazine that it you would have to have a huge number of rounds (like ~20,000) go through the weapon before you would see a significant deterioration caused by steel vs. brass.
I've always shot brass. I can't ever remember a shortage quite as bad as this one, although I was well stocked during the last one and may just not have been sensitive to it.
What I certainly do notice is a very serious unavailability of weapons of all kinds right now. My wife wants to spend her Trumpbux on an AR, and I have not been able to find a Wylde 223/556 anywhere online for almost three months. Also shotguns; no Mossbergs, none of the better Remingtons, many 45s and nines are way overpriced.
Have you tried Palmetto State Armory for the AR-15? They sell a lot of kits which should be pretty easy to assemble. That might be the way to go, seems like that would be more available. It’s a good company I’ve bought from them before.
I was in the Kentucky Gun Company the other day to use the range and they looked pretty well-stocked for weapons. They do have a good online presence. It is a good family owned company.
Kygunco.com