Replaced one of them. But now I can drive at night again, have use of my high beams (for the first time since owning my car), and my airbag light isn’t on ever again.

This is the part that I believe was the culprit. I have never seen anyone post anything online about this part being the reason for the headlight switcher not working on a Miata, so I thought I’d point this out as a potential solution for someone else in the same boat.

I didn’t take a picture of the good one, but it wasn’t sitting so high and flimsy with the spring like the one above. I sanded and put 100% silicone grease on the contacts all through out the switch like I did before:

This time though my results were better, in that with the little part replaced it now functions 100%. Maybe I damaged the other one the first time somehow, I don’t know, but it works now so whatever.