I had my entire front and rear brakes replace for squeaking under warranty. Mines a 2013 S Model, tbh i thought it was normal cause that's what one my dealer said. Usually when I start the car the first 5-10 minutes stop i hear squealing I thought my brakes were low, took it to the dealer told them I had that problem since day one. Entire front/rear brakes replace and no more squealing since today . there was a TSB for it but you gonna find it.
The steel wheels should have nothing to do with the sound your brakes make. It sounds like you need an aftermarket brake pad, and there are many to choose from. Ceramic pads do not dust as much, but tend to be harder, which can contribute to brake squeal. Organic pads are softer and quiet, and wear quicker with more dust. It's a tradeoff.